Authors:Heriansyah Putra, Hideaki Yasuhara, Naoki Kinoshita, Muhammad Fauzan Pages: 1 - 5 Abstract: The applicability of bio-chemical grouting as the environmentally friendly and economically method for liquefaction remediation was evaluated. Several combinations of organic and in-organic precipitations methods were conducted to obtain the optimum grouting solution. Organic precipitation method employs a bio-agent of urease enzyme to dissociate urea into ammonium and carbonate ions. The produced carbonate ions are precipitated as calcite crystals in the presence of calcium ions. Meanwhile, the in-organic methods were performed using chemical compounds only, without the bio-agent. Unconfined compressive strength (UCS) tests were performed to evaluate the applicability of the grouting solutions for improving the soil strength. Grouting solution is injected into the prepared sand samples. The sand samples with a relative density of 50% were treated with one and two PV for 3-day curing times. The experimental results showed that the organic precipitation method produced the high precipitated amount and resulted in the significant improvement in the strength of the treated sand. The presence of the precipitated materials within the grains of soil generated the strength of 272 kPa. The results of this study have elucidated that the organic precipitation method composed of calcium chloride, magnesium sulfate, urea and enzyme of urease may be an alternative soil-improvement technique to prevent the liquefaction susceptibility. PubDate: 2020-05-19 DOI: 10.9744/ced.22.1.1-5 Issue No:Vol. 22, No. 2 (2020)
Authors:Asdam Tambusay, Benny Suryanto, Priyo Suprobo Pages: 6 - 12 Abstract: This paper presents the application of a low-cost digital image correlation (DIC) system for automated crack mapping. The system employed makes use of a conventional digital camera, a remote image recording controller, and an open-source digital image correlation MATLAB software Ncorr. To showcase the potential of the proposed system, two case studies involving general structural and material testing were undertaken. In the first series, the DIC system was used to study the fracture processes in a reinforced concrete beam and to investigate the influence of key input parameters on the spatial quality of strain maps obtained from the DIC analysis. In the second series, the application of the DIC method was expanded to assist in the study of complex multiple micro-crack formations in ductile cement composite testing. It is shown that the strain maps obtained from the DIC technique have a close resemblance to the actual crack patterns PubDate: 2020-05-19 DOI: 10.9744/ced.22.1.6-12 Issue No:Vol. 22, No. 2 (2020)
Authors:Philip Baki OZIGI, Lawrence Zahemen TULEUN, Alao Abdullahi JIMOH Pages: 22 - 28 Abstract: This paper reports on the flexural strength behaviour of Apa reinforced stabilized lateritic soil beams. The potential of using timber as a reinforcement material is because timber is abundant, cheap and locally available compared to conventional steel. Apa timber possess a tensile strength of 68.34 N/mm2. Experimental and Finite Element Analysis using ANSYS 15 were carried out to determine the flexural strength of Apa reinforced lateritic soil beams. The results showed an increase in the load-bearing capacity with increase in the percentage area of Apa reinforcement used in Lateritic soil beams. BS 8110-1:1997 requires that area of reinforcement for beams should not exceed 4%. At 4 percent area, the flexural strength of the Apa reinforced lateritic soil beams (ALB) was 0.763 N/mm2 with corresponding load capacity of 3.435 kN which is slightly higher than the steel reinforced lateritic soil beams (SLB) of 0.740 N/mm2 with corresponding load capacity of 3.329 kN obtained in the report PubDate: 2020-05-19 DOI: 10.9744/ced.22.1.22-28 Issue No:Vol. 22, No. 2 (2020)
Authors:Andi Andi, Jani Rahardjo, Fendy Fendy Pages: 52 - 58 Abstract: Rework can bring negative effect to construction project. This research aims to identify the importance level of factors causing reworks in structural, finishing, and mechanical, electrical and plumbing (MEP) works by a way of importance performance analysis (IPA). In order to reach this objective, the research evaluates the degree of occurrence the factors in each type of works and analyzes the level of difficulty in preventing the occurrence of the factors. The results are based on questionnaire survey, involving general and MEP contractors in Surabaya. Design related factors are the most frequent and most difficult to prevent in structural and finishing works. In MEP works, the most frequent factors are tight construction duration and unclear instructions from owner and designer; whilst insufficient owner’s capital is the most difficult to prevent. The research finds two factors that have high importance level, i.e. design changes and insufficient detail drawings. PubDate: 2020-10-06 DOI: 10.9744/ced.22.2.52-57 Issue No:Vol. 22, No. 2 (2020)
Authors:Benny Suryanto, Joshua Kiyoshi Suryanto Pages: 59 - 67 Abstract: The four-point flexural test is now making headway as an alternative laboratory investigative technique for determining the tensile properties of Engineered Cementitious Composite (ECC) to the more traditional, direct/uniaxial tensile test. As the fundamental mechanics of ECC specimens tested in four-point flexure are well understood, it is possible to develop a simple relationship between flexural test results and the tensile properties of this cement composite. This paper extends this development and aims to provide accessible and quick calculation of the tensile properties of ECC via a virtual test environment. To this end, attention is directed towards the test configurations developed earlier at Heriot-Watt University, the University of Michigan, and Sepuluh Nopember Institute of Technology. In this paper, the technical background employed in creating the virtual environment and the computer implementation using the JavaScript programming language are presented. The prototype virtual environment is freely available via the Internet at https://ecc-calculator.netlify.app/. PubDate: 2020-10-06 DOI: 10.9744/ced.22.2.58-66 Issue No:Vol. 22, No. 2 (2020)
Authors:Agus Setyo Muntohar, Nurul Fata, Apiniti Jotisankasa, Kuo-Hsin Yang Pages: 68 - 74 Abstract: Some slopes in Yogyakarta, Indonesia, were covered by volcanic soil of the quaternary deposit of Merapi volcano. Typically, the soil layers of the slope consist of fine sand or silty sand. During the wet season (November – February), the slope is prone to instability due to rainfall infiltration. This paper presents the field suction monitoring of silty-sand slope. A 2.57 m high slope at Universitas Muhammadiyah Yogyakarta campus was instrumented with a mini tensiometer, moisture probe, and rain gauge to study the effect of suction on the slope stability during rainfall in wet season. The investigation shows that the rainfall decreases the suction and increase the moisture of soil. This situation leads to slope instability. The factor of safety fluctuates corresponding to the rainfall intensity. The lowest factor of safety was attained on 30 December, in which the rainfall intensity is the highest, i.e. 48 mm/day. PubDate: 2020-10-06 DOI: 10.9744/ced.22.2.67-73 Issue No:Vol. 22, No. 2 (2020)
Authors:Pamuda Pudjisuryadi, Andre Halim, Alexander Keith Kandiawan, Benjamin Lumantarna Pages: 75 - 81 Abstract: Deficient structures can be strengthened using various methods, and installing damper devices is one of such methods. In this study, effectiveness of Vorspann System Losinger (VSL) Gensui Damper to improve structural performance of deficient building with semi-rigid floors is investigated. The considered building is subjected to spectrum consistent ground accelerations generated from El Centro 18 May 1940 earthquake N-S and E-W components in accordance to Indonesian Seismic Code (SNI 1726:2012) for Mataram City. Modified Simplified Sequential Search Algorithm (MSSSA) and Optimum Damper Allocation Method (ODAM) methods are used to efficiently placed the dampers on the building until allowable drift limits specified by the code are met. Results show that installation of VSL Gensui Dampers can effectively reduce structural drifts. Further, it should be noted that the placement of dampers must be well distributed among frames in the same story, since their drifts may differ significantly in building with semi-rigid floors. PubDate: 2020-10-06 DOI: 10.9744/ced.22.2.74-80 Issue No:Vol. 22, No. 2 (2020)
Authors:Joko Purnomo, V. Octaviani, P. K. Chiaulina, Jimmy Chandra Pages: 82 - 93 Abstract: Lateral deformations of reinforced concrete (RC) frames under extreme seismic excitation are highly affected by the stiffness of their beam-column joints. Numerous models have been proposed to simulate the responses of RC beam-column joint under cyclic loading. Development of RC beam-column joint model based on macro modeling using spring elements becomes more popular because of its considerably simple application for seismic performance evaluation purposes. In this study, a simple modification to previously developed macro-spring element-based model for RC beam-column joint is done and is used to simulate the behavior of seven external and five internal RC joints under cyclic loading in SAP2000. The model consists of several spring elements to define column, beam, joint, and bond-slip responses according to its individual moment-rotation relationships. Overall, the analysis results show that the modified model can simulate well the cyclic behavior of RC beam-column joints when are compared to previously available experimental results PubDate: 2020-10-06 DOI: 10.9744/ced.22.2.81-92 Issue No:Vol. 22, No. 2 (2020)
Authors:Antoni Antoni, Stacia Dwi Shenjaya, Maria Lupita, Samuel Santosa, David Wiyono, Djwantoro Hardjito Pages: 94 - 100 Abstract: Circulating fluidized bed combustion (CFBC) is a newer type of burner that employ a circulating process to burn fuel effectively. CFBC burning process is gaining more popularity due to its compact size, high efficiency and lower burning temperature compared to the pulverized coal combustion (PCC) burner. The CFBC burner produces fly ash with different physical properties compared to the PCC burner, i.e. the fly ash is not rounded, and required higher water content for comparable workability. The CFBC fly ash also has a high sulfur content that is detrimental for hardened concrete. Due to its drawbacks, the CFBC hardly used as cementitious material and geopolymer precursor. This study focuses on comparing variations in the concentration of NaOH solution and variations in the ratio of alkaline activators to the setting time and compressive strength of geopolymer mortars on a new class of CFBC fly ash, which have low sulfur content. The concentrations of NaOH solution were 6M, 8M, 10M, and 12M, while the alkaline activator ratios used were 3.0, 2.5, 2.0, 1.0, and 0.5. It was concluded that the low sulfur CFBC fly ash has a potential to be utilized as geopolymer precursor, however, with a shortcoming in its high water demand. The CFBC fly ash used in this study resulted in a geopolymer matrix with good compressive strength and stability. The water demand varies with the fly ash sampling time shows the challenges in the utilization of the fly ash. The highest mortar’s compressive strength, 33.4 MPa at 90 days was achieved at NaOH concentration of 8M and ratio of sodium silicate solution to sodium hydroxide solution of 2.5 with excellent stability. PubDate: 2020-10-06 DOI: 10.9744/ced.22.2.93-97 Issue No:Vol. 22, No. 2 (2020)
Authors:Harijanto Setiawan, Ferianto Raharjo, Ay Lie Han Pages: 101 - 108 Abstract: Innovation is one of the key success factors of contractors to achieve sustainable business. However, studies about innovation cannot be generalized to all business sectors. Therefore, special study about innovation that focuses on contractors in Indonesia is needed. The study is aimed to explore the process of innovation development in contractors, based on innovation value chain (IVC) approach. The qualitative analysis on the data that is collected from in depth interview with top managers of big contractors in Indonesia is carried out. This study found that innovations are generated mainly by project teams because they are involved directly in the project activities. The next phase is to test the idea of innovation in the selected projects in order to assess whether the innovation works well or not. Finally, the selected innovations will be set as a company standard and will be implemented in the subsequent projects. PubDate: 2020-10-06 DOI: 10.9744/ced.22.2.98-104 Issue No:Vol. 22, No. 2 (2020)
Authors:Zakwan Gusnadi, Paulus Pramono Rahardjo, Aswin Lim Abstract: The soil improvement method by vacuum preloading combined with prefabricated vertical drain (PVD) has several advantages including increasing the stability of subgrade and reducing embankment material for preloading purposes. However, the vacuum pressure used for improvement is not only distributed in the improvement area but to a certain distance around the improvement area. This study will discuss lateral displacement existing driven piles due to soft soil thickness variation on vacuum consolidation. The analytical method used is the finite element method with the ABAQUS program. Then analyzed with several variations in the thickness of soft soils (10.5 meters, 15.5 meters, 18.5 meters, 20.5 meters, and 26.5 meters). Lateral displacement with variations in the thickness of soft soil ranged from 55 mm to 130 mm at 80 days of improvement times. The bending moment occurs up to 244.6 kN.m exceeds its ultimate structural capacity. Issue No:Vol. 22, No. 2
Authors:Christian Vincent Pranoto, Edward Leonardo Abstract: Concrete structural elements have several weaknesses, namely low tensile strength, brittle, and susceptible to cracks. Concrete cover delamination premature failure of Fiber Reinforced Polymer (FRP) reinforced concrete (RC) beams remains a problem which hinders FRP usage as flexural beam reinforcement. To overcome this, the U-Wrap anchoring system was designed as efficient as possible using Strut-and-Tie Modeling to prevent premature failure. The experiment was done using fifteen 1200x150x150 mm beams, with longitudinal reinforcement D10, Ø8-50 mm stirrups, and designed concrete strength 25 MPa, with twelve beams reinforced with different U-Wrap configuration to investigate its effectivity and efficiency. The loading method is two-point load, and data analysis method is Digital Image Correlation. Results of study test specimens obtained differences in crack patterns, ductility, bending capacity, and stiffness compared to RC beams. The study concluded U-Wrap installation may prevent premature failure, and installation of more than one U-Wrap do not significantly affect FRP reinforced beams ductility, bending capacity, and stiffness. Issue No:Vol. 22, No. 2
Authors:Jacqueline Nyirajana, Akinwale Oladotun Coker, Folake Olubunmi Akintayo Abstract: Insufficient control system cause conflicts of the movement at an intersection especially in cities that result in various problems, including accidents. This study aimed to provide a well-designed pre-timed signal for the efficient traffic flow at Musanze intersection, thus reducing unnecessary stops and delays. The traffic surveys were conducted to gather traffic volume data. The standard procedures of the Manual on Uniform Traffic Control Devices and Highway Capacity Manual were used to determine design parameters. A 2-phase signal-control plan was provided, and the critical volumes were respectively 922 veh /h and 614veh/h in the West and North approach. The cycle length, green times of phase 1, and 2 were evaluated as the 60s, 33s, and 22s, respectively. The minimum green time required by pedestrians to cross the intersection was 10 seconds. The time allocated to the pre-timed signal was expected to improve the traffic flow at the intersection. Issue No:Vol. 22, No. 2
Authors:Pierre Clément NZARERWANGABO, Jacqueline Nyirajana, Nsanzimfura Theoneste Abstract: Soil is the most widely used material in a highway system, either in its natural form or in a processed form. In addition, all pavement structures eventually rest on soil foundation. The construction cost can be considerably decreased by using local soils for lower pavement layers like the subgrade. The formation of undulations, corrugations, upheaving, and rutting is generally attributed to the poor subgrade conditions. This study investigated the feasibility of using SCBA to improve the geotechnical properties of the soil. Clay soil is used with different percentages of bagasse ash, like 0%, 3%, 6%, 9%, and 12%. Various tests like the sieve analysis test, Atterberg limits test, standard proctor test, and CBR test have been performed to determine its effect on strength parameters. The sieve analysis test was for determining the properties of the soil sample. Its result indicated that the soil is clay with a grey color. Atterberg limits test results suggested that the plasticity index decreases with an increase in the percentage of SCBA. Standard proctor test results indicate that the optimum moisture content increases with an increase in the rate of SCBA. The maximum dry density decreases with an increase in the percentage of SCBA. CBR results indicate that the CBR value is increased up to a replacement of 9% of SCBA. With further increase in the rate of SCBA, the CBR value decreases. These results show that SCBA can be used as a stabilizer with its optimum percentage of 9% to increase the CBR value of subgrade soil. Issue No:Vol. 22, No. 2
Authors:Sulih Dhanianto, Abdul Rochim, kartono wibowo Abstract: Glendoh is a traditional market located in Grobogan Regency. Due to a huge amount of waste produced and located in urban area, this market will be relocated in 2022. Based on detailed Engineering Design document made by the planning consultant, the relocation project costs Rp. 13.587.000.000 (Thirteen billion five hundred and eighty-seven million rupiah). To minimize the financial budget and maintain the project quality, a value engineering analysis is needed to select some applicable design alternatives. Through this value engineering analysis, problems can be identified and the main purposes of the project can be achieved with minimum costs, but optimal results. This study had three main purposes; first, to figure out what components were applicable as design alternatives with the highest net benefits; second, to estimate the cost efficiency of the design alternatives for Glendoh Traditional Market development project; and third, to calculate project value and life cycle costs of the design alternatives after the value engineering analysis was carried out. This study was conducted using a qualitative and quantitative descriptive approach. A work plan, in accordance with the SAVE International Value Standard 2007, was used as data analysis methods. There were five phases included in the method; the information phase, the function analysis phase, the creativity phase, the evaluation phase, and the development phase. The tools used to analyze data were the information phase (Pareto Analysis), the functional analysis phase (Functional Analysis System Technique), the creativity phase (Checklist), the evaluation phase (Paired Analysis Comparison and Decision Matrix) and the development phase (Life Cycle Cost Analysis and Implementation Time Efficiency Analysis). This study concluded that galvalume roofs and a 10 cm thick K250 wiremesh concrete were applicable as design alternatives with the highest net benefits for Glendoh Traditional Market development project. Likewise, this study found out that the efficiency level of the design alternative on the galvalume roofs with construction cost of Rp. 334.688.637.44 had a percentage of cost efficiency of 60,95%, while a 10cm thick of wiremesh K250 concrete with construction cost of Rp. 1.054.803.322.22 had a percentage of cost efficiency of 9,84%. Furthermore, it was estimated that after analyzing the value engineering, the total value of Glendoh Traditional Market project was revealed to be Rp. 11.714.219.849.03, where a life cycle cost for each design alternative; the work of galvalume roofs costed Rp. 937.807.786.37 with the a life cycle saving percentage of 60.95%, while the work of a 10 cm thick K250 Wiremesh Concrete costed Rp. 1.562.255.456.40 with a life cycle saving percentage of 25.61%. Issue No:Vol. 22, No. 2
Authors:Muhammad Karami, Dwi Herianto, Siti Ofrial, Ning Yulianti Abstract: This research analyses the characteristics of travel time reliability for the road network in Kota Bandar Lampung. Therefore, travel time consists of access, wait and interchange time, while its reliability deals with variations of in-passenger/private cars time. Survey of travel time on each road was carried out for 12 hours (from 06.00 to 18.00) for five working days. Furthermore, the buffer time method was used to measure the characteristics of time travel reliability consisting of five measuring tools, namely planning time, planning time index, buffer time, buffer time index and travel time index. This research found that the temporal effects are the main factor that tends to affect travel time, whereas network effects are the second factor that tends to affect travel time. Furthermore, the regression equation was developed to express the effect of planning time (TPlan) and free-flow travel time on average travel time . Issue No:Vol. 22, No. 2
Authors:Hafnidar A. Rani Abstract: The community is the greatest victim impacted by natural disasters, and in most cases, these communities are not well prepared to overcome the effects even though historically they have endured and survived a series of disasters. Factors that contribute toward large numbers of victims being greatly affected include ignorance of the dangers, vulnerabilities, and capacities to overcome in the neighborhood. A paradigm shift is needed to encourage communities to participate as a whole in overcoming these disasters, as they have local wisdom and better understanding of their environmental condition. Participation by communities include components of assessing hazards, vulnerabilities, and capacities to reduce risk disasters effects, thus this research aimed at assessing these three components in the Meuraxa Sub-District, Banda Aceh City, in Aceh Province of Indonesia. The method used was participatory rural appraisal involving the surrounding community. Based on the assessment of the three aforementioned components, it was found that hazards occurring in this location include strong wind, flood, earthquake, and tsunami. Physical vulnerability is that the residential areas are location near coastal areas as well as being located in lowland areas, while economic vulnerability is that not all communities have fixed incomes, some depending on natural resources. The escape buildings used in evacuation are the potential capacity in the Meuraxa Sub-District. Meanwhile, institutional capacity is the existence of a disaster resilience community trained to respond to disasters, as was established post-tsunami 2004, however there is no regeneration. The output of the study resulted that the disaster risk level in Meuraxa Sub-District is high in which the vulnerability is more dominant than capacity, where there is lack of understanding of hazards, vulnerabilities, and capacities to improve disaster risk levels at the location of study. Issue No:Vol. 22, No. 2
Authors:Yusep Muslih Purwana Abstract: Plasticine is an artificial material made from solids such as gypsum, lime, mixed with petroleum jelly or micro wax and acid fat. The properties of plasticine are likely similar to natural clay and is influenced by oil content. The information about mechanical properties of plasticine is still very rare, and as such the study on it is riquired and must be conducted intensively. The preliminary laboratory study has been conducted to understand the behaviour of plasticines. Microwax and petroleum jelly based plasticines were utilised with the variation of oil content, whereas kaolin clay with the variation of water content is utilised as a reference material. The study is focusing on the stress-strain behaviour for both microwax and petroleum jelly based plasticines compared to the stress-strain behaviour of kaolin clay. This paper reports the result of preliminary investigation regarding the use of plasticine as an alternative artificial material for substitution of clay in soil modeling. Some engineering properties from unconfined compression strength (UCS) test and hand penetrometer are shown. The result indicates that the stress-strain behaviour of plasticine resembles the stress-strain behaviour of kaolin clay. The plasticine is suitable as a substitute cohesive material and it has a potential to be utilised for geotechnical material modelling in the future. Issue No:Vol. 22, No. 2
Authors:Prima Juanita Romadhona, Titisari Puspadewi Abstract: In early 2020 the COVID-19 pandemic happened in all countries including Indonesia. This affected the Damri Bus as a transportation that serves Yogyakarta International Airport route which still operating during pandemic condition. The research aim is to evaluate the performance of Damri Bus especially Condongcatur Terminal-Yogyakarta International Airport and Sleman City Hall-Yogyakarta International Airport routes during COVID-19 pandemic. The performance parameters evaluated were headway, waiting time, circulation time, travel speed, passenger volume, load factor, vehicle travel distance, and vehicle availability. The method used in this study was quantitative empirical descriptive that refers to the related standards. The results of the analyzed routes had met the standards except for passenger volume. The scenario of physical distancing inside the bus resulted 64% of load factor on Condongcatur Terminal-Yogyakarta International Airport Route and 80% of load factor on Sleman City Hall-Yogyakarta International Airport Route. Issue No:Vol. 22, No. 2
Authors:Bao Ngoc Nguyen Abstract: The way Vietnamese construction practitioners perceive waste is homologous with that of lean construction. This paper aims to provide valuable insight into the current status of waste-value and productivity perception, thereby assessing prospects of practising lean construction in developing countries like Vietnam. The author undertook the questionnaire survey into construction practitioners, analysing 68 responses across different regions and different job responsibilities. This paper highlights the distinctness of lean-thinking-based waste other than material misuse, poor decision, and corruption. People are more aware of the types of waste that are often recognisable on-site, namely unnecessary movement, defect/correction, unnecessary transport. The survey results also show that the two groups with a reasonably good awareness of waste are real estate developers and public bodies. People working at public authorities appeared to have the greatest satisfaction with current workplace productivity, whereas educators seemed neutral in a sense. The sample size, which is too small, may produce low statistical power and inflated false discovery. Vietnamese construction practitioners appeared quite willing to accept major reforms and transformation. Understanding the gap in waste perception between lean perspective and reality, thereupon framing the roadmap to adopt lean construction. Issue No:Vol. 22, No. 2
Authors:Sugeng Wijanto, Takim Andriono, Jovita Augusta Tanudjaja Abstract: Unreinforced masonry walls (URM) in old buildings are vulnerable to collapse upon receiving high lateral inertia force due to earthquakes. However, a high strength fiber material such as Kevlar fiber has been identified as able to improve the URM-Wall performance, especially in shear strength enhancement. In this research, the seismic performance of an URM-Wall was analysed using SAP2000 by modeling the wall with three dimensional solid elements. Solids and springs as link connectors were assigned to represent the masonry behavior. The aim of this research is to compare between results obtained from the computer analyses and the previously conducted laboratory experiments. The effectiveness of Kevlar material installed in the diagonal directions of both wall surfaces was investigated. It was found that the failure mechanism shown by the SAP2000 model is similar to the laboratory test results. Issue No:Vol. 22, No. 2
Authors:B. Sri Umniati, Dewi Kartika Sari, Siti Nur Rahmah Anwar, Mohammad Sulton, Roro Sulaksitaningrum Abstract: Penelitian ini menginvestigasi kapasitas beban lateral statis dinding panel beton ringan berbahan baku agregat ringan yaitu butiran EPS sebanyak 2,5% mengganti agregat kasar dan 30% fly ash menggantikan semen. Sebanyak 6 buah benda uji panel dinding berdimensi panjang 90 cm, lebar 60 cm dan tebalnya 10 cm dengan variable jenis tulangan polos dan ulir diameter 5mm diuji dengan beban lateral static. Dari hasil uji terbukti bahwa dinding beton ringan mampu menahan beban lateral. Adapun besar beban lateral yang dapat ditahan dinding adalah benda uji dinding ulir 1 memiliki kemampuan menahan beban lateral statis yang paling tinggi yaitu 25,72 KN setara dengan 2622,71 kg dan untuk tulangan polos beban tertinggi yang mampu diterima sebesar 17,23 KN setara dengan 1756,97 kg. Beban terendah terjadi pada dinding ulir 2 beban yang mampu diterima sebesar16,05 KN setara dengan 1636,64 kg karena terjadi rigid body movement. Dari capaian hasil uji beban lateral tersebut dapat ditunjukkan bahwa dinding tulangan ulir memiliki kemampuan menahan beban lateral static yang lebih besar daripada dinding dengan tulangan polos.Simpangan terbesar terdapat pada dinding polos 2 yaitu 28,60 mm karena terjadi kerusakan pada dasar sloof dan simpangan terendah terjadi pada dinding polos 1 yaitu sebesar 4,20 mm. Pola keruntuhan yang terjadi adalah kegagalan lentur yaitu terjadi pada dinding ulir 1, ulir 3 dan polos 1 sedangkan ulir 2, polos 2 dan polos 3 mengalami rigid body movement sehingga terjadi slide shear pada dinding. Issue No:Vol. 22, No. 2
Authors:Dian Pratiwi Abstract: Pacitan Bay is one of the area that have the tsunami potential. Casuarina eqisetifolia planting program as natural barrier in Pacitan Bay had started since 2008. The evaluation of Casuarina eqisetifolia was conducted by field survey investigation and simulating 3 different scenarios of tsunami such as a condition along Pacitan Bay without vegetation, a condition with existing vegetation and a condition with the increase of width and vegetation length using TUNAMI Modified (beta version).The result showed that the effectiveness of vegetation may not as good as expected due to tsunamis because some of vegetation was dried or even uprooted. Simulation result showed that the present condition is insufficient to reduce the wave, in addition at the unprotected area, the effect of tsunami was larger than the condition when there was no vegetation along Pacitan Bay. The third scenario can be used as the recommendation in Pacitan Bay. Issue No:Vol. 22, No. 2
Authors:Leghouchi abdelghani, Djemai mohammed Abstract: The failure of a dam results in major floods in the downstream zone, which can lead to catastrophic indemnities. Therefore, it is necessary to predict the flooding resulting from a potential dam break and plan the suitable measures to mitigate the damages. In this respect, numerical modeling is increasingly adopted to simulate and understand the hydraulic mechanism of the phenomenon. In addition, Geographic Information Systems (GIS) are currently indispensable for effective analysis and management of disasters in this field. The present study aims at predicting the consequences associated with the propagation of the dam break floods that may occur after the failure of the Taksebt dam and suggest an efficient emergency action plan for mitigation purpose. To achieve the objectives of this study, the hydrodynamic model HEC RAS 2D was used to simulate the dam break wave propagation, which gave an estimate of the hydraulic characteristics downstream the dam, and GIS was used to map the results. Geospatial analysis of the modeling results conducted in GIS showed that many residential areas are considered to be in danger in case of the Taksebt dam break event. Based on the obtained results an emergency actions plan was suggested in order to moderate the causalities. The integration of 2D hydraulic modeling and GIS showed great capabilities in providing realistic view of the dam break wave propagation which facilitated assessing the risks and proposing the appropriate mitigation measures. Issue No:Vol. 22, No. 2
Authors:Said BOULAARES, Djamel Boutagouga, Abdelkader HOUAM Abstract: Every experimenter needs a method to carry out his research. The choice of method depends on the structure of the research, the hypotheses, the phenomena studied but above all the time and budget provided. These are real concerns for researchers. In this article, we adopt the method known as experimental design, as a solution to these concerns, using the software MINITAB 19. The objective is to shed some light on the effect of the interaction between different factors on the Behavior of hollow columns in welded stainless steel filled with Concrete. Based on the results obtained, it is confirmed that when combining two independent parameters, one of which has a high effect and the other has a low one, this combination (interaction) gives a considerable effect on the carrying load of the composite columns Issue No:Vol. 22, No. 2
Authors:Said BOULAARES Abstract: Every experimenter needs a method to carry out his research. The choice of method depends on the structure of the research, the hypotheses, the phenomena studied, but above all it relies on the time and budget provided. These are real concerns for researchers. In this article, we adopt the method known as experimental designs, as a solution to these concerns, using the software MINITAB 19. This software offers a wide range of statistical analysis function and graphic tools. Using a complete factorial design, which required us to use 16 tests; we examined four factors, two of which showed a significant effect on the experimental carrying load of the Composite columns. These factors (parameters) are: plate thickness, the geometric shape, the compressive strength of concrete at 28 days and the consistency of concrete.The purpose of this study is to shed some light on the effect of the interaction between different factors on the behavior of hollow columns in welded stainless steel filled with Concrete Issue No:Vol. 22, No. 2
Authors:wayan muka Abstract: .This study aims to determine the waste level, waste cost and the method of using cutting optimization pro software whether it can minimize reinforcing iron waste optimally. Primary data collection methods were carried out by interview and observation, while secondary data were obtained from SDN 3 Peguyangan project. From these data, then making a bar bending schedule to calculate the waste level and waste cost. The length of the iron requirement on the bar bending schedule is input into the cutting optimization pro software. The result of the analysis shows that the waste iron level 6 mm is 9.1%, plain iron ᴓ8 mm 5.7%, plain iron ᴓ10 mm 3.3%, threaded iron D13 2.3%, and threaded iron D16 2.4%. The average waste generated from the five types of iron is 4.5%. The waste iron cost of ᴓ6 mm costs Rp. 491,062.00: plain iron ᴓ8 mm Rp. 3,313,569.00; plain iron ᴓ10 mm Rp. 1,505,565.00; iron screw D13 Rp. 519,652.00 and threaded iron D16 Rp. 2,792,373.00. The total waste cost arising from the five types of iron is Rp. 8,620,222.00. From the analysis of cutting optimization software pro plain iron ᴓ6 mm, the waste is 0%, plain iron ,8 mm 0.3%, plain iron ᴓ10 mm 0.02%, threaded iron D13 2.1%, and threaded iron D16 0.6%. The average waste generated from the five types of iron is 0.5%. The results of the comparison with conventional methods show that cutting optimization pro software can minimize waste optimally by 4%. From the analysis of cutting optimization software pro plain iron ᴓ6 mm, waste is obtained as much as 0%, plain iron ᴓ8 mm 0.3%, plain iron ᴓ10 mm 0.02%, threaded iron D13 2.1%, and threaded iron D16 0.6%. The average waste generated from the five types of iron is 0.5%. The results of the comparison with conventional methods show that cutting optimization pro software can minimize waste optimally by 4%. From the analysis of cutting optimization software pro plain iron ᴓ6 mm, waste is obtained as much as 0%, plain iron ᴓ8 mm 0.3%, plain iron ᴓ10 mm 0.02%, threaded iron D13 2.1%, and threaded iron D16 0.6%. The average waste generated from the five types of iron is 0.5%. The results of the comparison with conventional methods show that cutting optimization pro software can minimize waste optimally by 4%.Keywords: Waste, Reinforcement, Cutting Optimization Software Pro Issue No:Vol. 22, No. 2
Authors:Zalfa Maulida Ihsani, Heriansyah Putra Abstract: This study discussed the applicability of the calcite precipitation method to repair the concrete's crack. The grouting solution of Enzyme-Mediated Calcite Precipitation (EMCP) was modified by adding milk as a catalyst in calcite formation. Cracks in concrete samples were made when the concrete was 28 days with a width of 0.1-0.3 mm. The EMCP solution composed of urease, urea, CaCl2, and milk was injected into the cracked concrete sample, and its effect on permeability and compressive strength tests were evaluated. The result shows that the optimum composition of milk used in the formation of calcite had a concentration of 5 g/L with an initial preparation temperature of 70oC, which produced 26% higher than the initial EMCP solution. The mechanical test results show that the reduction of coefficient of permeability of 92.23% compared to the cracked sample and the improve strength up to 98.75% of the non-cracked sample were obtained by three circles injection. This study elucidated that milk utilization as a catalyst material in repairing cracks with the EMCP method is a potential method for crack-healing concrete. Issue No:Vol. 22, No. 2
Authors:Andrianto Muliawan Permana Abstract: Jakarta and its infrastructure growth encourage improvement in dealing with construction problems. One of the problem often arise is land subsidence due to construction loads and natural consolidation processes. This occurrence is commonly referred to as settlement. Soft soil which undergo a consolidation settlement process is also called as underconsolidated soil (UC). The aim of this study is to characterize the soft soil layer in Central Jakarta using CPTu and laboratory test. OCR values are interpreted using Su method, Bq and Bq* method. From the 94 drilling data and 30 CPTu data collected, it is known that the soft soil layers in Central Jakarta are located at a depth of 0 – 25 m with high moisture content, high void ratio, high LI and high Cc values. From the interpretation of CPTu, the soil layer are found to be underconsolidated in some areas. Issue No:Vol. 22, No. 2
Authors:Sayahdin Alfat Abstract: Investigation of spacing and alignment effect between two small-holes on crack growth simulation has been finished. In the study, some points would be shown, as follows: (1) crack growth behaviour, (2) the von Mises stress distribution, and (3) energy profiles, through variation of spacing and alignment two small-holes. As idealization, the author introduced some assumptions, as follows; (a) material was homogeneous and isotropic with physical properties, Young's modulus (E) = 70 GPa, Poisson's ratio () = 0.35, and energy release rate , (b) the initial displacement is zero , and the body force is neglected . Some important targets have been achieved as follows: (a) the spacing between two small-holes did not affect the behaviour of crack growth significantly, but different from the alignment; (b) The size of the crack was proportional with increasing crack length; (c) During cracked process, the highest stress distribution occurred in the tip of crack and the lowest stress on center of crack; and (d) spacing and alignment variation would be effect on the material strength, material with was the soft material, but material with was otherwise. Issue No:Vol. 22, No. 2
Authors:Zenia F Saraswati, OFYAR Z TAMIN, Siti Rahma, Goldie Melinda Wijayanti Abstract: This work seeks to analyze the potential of regional campus buses in creating the accessibility needed by the wider community, affordable in terms of tariffs, efficient and supporting economic development and reducing emissions and waste generated in the Institut Teknologi Sumatera (ITERA) in Lampung, Indonesia. As a commitment to sustainability by planning ITERA Smart Bus Rapid Transit (Smart BRT ITERA) form of collaboration with the Ministry of Transportation of the Republic of Indonesia. ITERA, in this case, acts as the operator of 10 buses grants by the Ministry to serve this activity. Through the framework of the concept of sustainable transportation, this research focuses on user satisfaction and affordability. As in the results based on data-driven in e-questionnaires, we examine the existing relationships between mode choice, travel time, willingness to pay, urban structure, and the potential to switch modes of the ITERA commuters. This research concludes out of 2 routes to serve daily activities to the campus needed scheduled rites six times a day during peak and non-peak hours with the bus tariff of 2,000 Rupiah and operational costs of 1,731 Rupiah for route 1 and 1,148 Rupiah for route 2.Given a high enough demand, ITERA can benefit from this program. This demand is still very vulnerable given their nature of service. Issue No:Vol. 22, No. 2
Authors:Toni Hartono Bagio Abstract: The development of technology in the last few years can not be denied that it has developed very rapidly, which can be very helpful in any kind of work. In building construction, reinforced concrete beam and columns calculations also utilizing that technology development. Calculations performed on the computer are faster and easier to complete and also reduced the error caused by humans. However, the use of computers has decreased because work that was previously only possible to do on computers can now be done on smartphones.Beam reinforcement, for tensile reinforcement (As) = Mn / (λ + γδ), and for compression reinforcement (As') = δ As, where: λ = fy (d - a / 2); γ = (fs '- 0.85 fc') (a / 2 - d ') and δ = (Mn fy - Cc λ) / (Mn fs' + Cc γ), while for colum reinforcement, without using M-N interaction diagram, to find Atotal, 1)Atot=1% Agross, 2) Atot= 8% Agross, 3) Atot is between (1% - 8%). At stage 1,2,3 to calculate c using Newton Raphson method, while for calculate reinforcement percentage is using divided by two methodThe program determines As, As’ and Astotal, the code is written using the Texas Instruments programming language, so that it can be applied to smartphones. Issue No:Vol. 22, No. 2
Authors:Augustine Kenechukwu Okechukwu Abstract: Access to uninterrupted electricity is key to the overall socio-economic development and growth of any nation. This paper evaluates the distribution of electricity to the residents in Agbani, Nkanu West L.G.A. of Enugu state; examining the number and duration of power outages and supply and also the factors affecting the supply and distribution of electricity. 100 questionnaires were equally distributed to the households of the four core areas, out of which 84 were retrieved (84%). Findings shows that the mean electricity supply is 5hours 33 minutes, with the most power outages being more than three, lasting between two to five hours. Fraud by service personnel was revealed as the major factor affecting supply and distribution of electricity. It is recommended that rapid response should be proffered by the government to curb the unreliable power supply and stiffer penalties meted out to all fraudulent personnel to help sanitize their service delivery. Issue No:Vol. 22, No. 2
Authors:novi andhi setyo purwono Abstract: Song Putri Reservoir is an artificial reservoir with the aim of irrigation channels for rice fields and flood control, this reservoir is located in Eromoko District, Kab. Wonogiri Sedimentation modeling in the Song Putri reservoir is needed to analyze the amount of sediment deposition against the Song Putri reservoir. To analyze the flow patterns and sediment distribution that occurs in reservoir reservoirs, SMS (Surface-water Modeling System) 8.0 software is used. This study aims to determine the flow patterns and effects of sediment distribution on reservoir reservoir changes. The data used include: Song Putri Reservoir technical data, daily rainfall data for 10 years (2009-2018), sediment data, reservoir inflow data, and bathymetry maps. To analyze the magnitude of inflow and outflow of Song Putri Reservoir, hydrological analysis using empirical methods is used, while sedimentation modeling simulation uses SMS 8.0 Software.Based on the simulation results the highest flow velocity in the 50 year return period is 0.097 m / s and the smallest is 0.00 m / s. Based on the simulation results of changes in the reservoir reservoir base for 720 hours (1 month) the values obtained in the return period of 50 years, 100 years and the highest 1000 years of 5.795 m and the smallest of 0.001 m, based on the calculation of prediction of sediment growth rates obtained the results of sediment growth rates with a percentage for a 50 year return period of 35.68% with a range of percentages between 19% - 21% and a percentage of 29.103% for a 100 year return period with a range of percentages between 22% - 24%, while the percentage growth rate of 1000 year return period sediments is 98 , 20% with a percentage range between 55% - 57%. Issue No:Vol. 22, No. 2
Authors:novi andhi setyo purwono Abstract: Song Putri Reservoir is an artificial reservoir with the aim of irrigation channels for rice fields and flood control, this reservoir is located in Eromoko District, Kab. Wonogiri Sedimentation modeling in the Song Putri reservoir is needed to analyze the amount of sediment deposition against the Song Putri reservoir. To analyze the flow patterns and sediment distribution that occurs in reservoir reservoirs, SMS (Surface-water Modeling System) 8.0 software is used. This study aims to determine the flow patterns and effects of sediment distribution on reservoir reservoir changes. The data used include: Song Putri Reservoir technical data, daily rainfall data for 10 years (2009-2018), sediment data, reservoir inflow data, and bathymetry maps. To analyze the magnitude of inflow and outflow of Song Putri Reservoir, hydrological analysis using empirical methods is used, while sedimentation modeling simulation uses SMS 8.0 Software.Based on the simulation results the highest flow velocity in the 50 year return period is 0.097 m / s and the smallest is 0.00 m / s. Based on the simulation results of changes in the reservoir reservoir base for 720 hours (1 month) the values obtained in the return period of 50 years, 100 years and the highest 1000 years of 5.795 m and the smallest of 0.001 m, based on the calculation of prediction of sediment growth rates obtained the results of sediment growth rates with a percentage for a 50 year return period of 35.68% with a range of percentages between 19% - 21% and a percentage of 29.103% for a 100 year return period with a range of percentages between 22% - 24%, while the percentage growth rate of 1000 year return period sediments is 98 , 20% with a percentage range between 55% - 57%. Issue No:Vol. 22, No. 2
Authors:Rizki Amalia Tri Cahyani, Ernawan Setyono, Yunan Rusdianto Abstract: Sulfate attack is common occurrence in concrete environments as sulfate ions are frequently present in soils, groundwater, and seawater. Enhancement of sulfate resistance will have great impact on improving the durability and service life of concrete structures. Supplementary cementitious materials, such as GGBFS, have been shown to possess positive influence on durability and the concrete properties. However, there is still limited study available on the durability of GGBFS-based concrete in Indonesia. In this study, the durability of concrete with varying amounts of GGBFS was evaluated in respect of combined action of magnesium sulfate attack and drying-wetting cycles. The extent of concrete degradation was measured by evaluating the changes in specimen mass and compressive strength. Results have shown that specimens without GGBFS exhibited highest mass loss and strength reduction. On the other hand, the addition of GGBFS up to 50% replacement levels has enhanced concrete resistance against sulfate attack. Issue No:Vol. 22, No. 2
Authors:Tanti Muliati Abstract: Pile-Pilecap behaviour is investigated utilizing fiber optic sensors to transmit information along the bored pile continuously at interval reading of 40 mm during each cycle of static loading test. The fiber optic cables were installed at two sides in the bored pile to pilecap, to monitor stress distribution under pilecap fiber optic also installed under pilecap. Pile-pilecap configuration is expected to achieve ultimate axial bearing capacity 190 ton x 250%. However failure occured while the test load increased up to 190% design load. From strain measurement by using Distributed Fibre Optic Sensor Technology information about load transfer, pile shortening, mobilized unit skin friction and mobilized end bearing at pile-pilecap can be obtained. Also fiber optic that installed under pilecap recorded strain at soil due load at pilecap. Issue No:Vol. 22, No. 2
Authors:Bondan Galih Dewanto, Ming Yang, Leni Sophia Heliani, Yanuar Haryanto, Banu Ardi Hidayat Abstract: After the occurrence of the 2010 Mw 7.8 Mentawai tsunami earthquake on the Sunda megathrust in Indonesia, a following 2012 Mw 6.2 earthquake occurred right east of the 2010 event, one of the areas that has a high coupling rate but the energy released is less, called Mentawai seismic gap. It is important for us to understand the seismic hazard of the Mentawai seismic gap for disaster mitigation purpose. Then, we therefore collected the GPS observations during 2010-2012 from 16 SuGAr stations to realize the coseismic displacements of the 2012 Mw 6.2 earthquake. The GPS data was processed using GAMIT/GLOBK 10.7 software to get the daily coordinates for every station, and further the coseismic displacement field have been solved based on the coordinate time series. The maximum and minimum displacement field occur in BSAT and MLKN stations, respectively. The coseismic source model has been completed using the kinematic model. From that, the energy accumulation detected in 2012 earthquake is Mw 6.2. The maximum slip distribution occurs at 8 km in depth with the value almost reaching 150 mm and show that the 2012 earthquake have filled some part of the Mentawai seismic gap. Issue No:Vol. 22, No. 2
Authors:Bondan Galih Dewanto, Yanuar Haryanto, Sanidhya Nika Purnomo Abstract: On January 27 2017, Indonesian government started building a new international airport in Yogyakarta Province, named Yogyakarta International Airport (YIA) to replace Adisucipto International Airport. It is a way to prevent the increase of passenger number. YIA is located near the beach which means it needs to be aware of natural disaster, such as tsunami and coastal flooding. One of the causes of sea water flooding is land subsidence phenomena. It could be monitored by using Sentinel-1 Interferometric Synthetic Aperture Radar (InSAR) data. To monitor the crustal deformation pattern in YIA area, the data that we used in this research are from 2016-2019 and it is in descending mode. We processed it in LiCSBAS software which is published by the Centre for the Observation and Modelling of Earthquakes, Volcanoes and Tectonics (COMET), UK. In the processing scheme, interferograms with many unwrapping errors are detected and removed via loop closure. Reliable time series and crustal deformation velocities are extracted using several noise indices with the help of masking. The results show the subsidence phenomenon in YIA area. The biggest number of subsidence is 25 mm. Issue No:Vol. 22, No. 2
Authors:Josephine Widyatmadja L Abstract: : Lots of researches on reinforced concrete beams have been done. One of the most discussed topic nowadays is research about structural reinforcement using Fiber Reinforced Polymer (FRP). Most researchers had observed the behavior of FRP on reinforced concrete beam for strength and ductility, meanwhile research about the effect of initial strain on the behavior of reinforced concrete beam with FRP is remotely observed. In this study, reinforced concrete beam with FRP will be tested by applying initial loads that causes variation of initial strain in each specimens. Variable of 0%, 50%, 125%, and 175% from the crack load (Pcrack) are used as initial loads. Specimen loading is carried out using the two – way point load method, concrete beam with Ø10 mm for compression and tension reinforcements, strirrup of Ø8 mm with 150 mm spacing, and design compression strength of 20 Mpa. The results of the specimen testing showed differences between plain reinforced concrete beam and concrete beam with FRP in crack patterns, ductility, strength, and stiffness. It can be concluded that the greater value of initial strain that occurs in the beam before the application of FRP will decrease the ductility and strength, but increase the stiffness of the beam. Issue No:Vol. 22, No. 2
Authors:Pamuda Pudjisuryadi Abstract: The stiffness of masonry infill walls is commonly neglected in design practice of Reinforced Concrete (RC) structures. In fact, the stiffness of masonry infill wall may significantly influence seismic performance and dynamic behavior of RC buildings. In this research, influence of masonry infill walls to the structural performance of a three-story RC frame is investigated. In addition, possible application of friction-based support is also studied. Full 3D non-linear time history analysis is conducted to observe behavior of the structure under two-directional ground motion. In the analysis, any failed elements are removed subsequently from the model to avoid numerical analysis problem. The result shows that the placement of masonry infill walls can significantly influence the structural behavior of RC structure. Inappropriate placement of masonry wall may lead the building undergo soft-story mechanism. It is also found that the use of friction-based support can effectively improve the seismic performance of the building. Issue No:Vol. 22, No. 2
Authors:Samsul A Rahman Sidik Hasibuan Abstract: : Flat slab is a reinforced concrete slab supported by column it may be added or not added drop panels or the column may be added column heads or without column heads and drop panels. The method design of flat slab that will be used is a direct design method where the method is to determine the minimum thickness of the plate that is reviewed based on the quality of steel that will be used. Moment distribution in the direct design method generates total moment which will then be distributed to each panel for the column strip and middle strip. Punching shear occurs in the critical cross-section area around the column heads and the drop panels so that the shear strength will be calculated based on the value of the shear strength that occurs and will be controlled by the shear strength of the quality of concrete used. This research will be analyzed numerically based on SNI 2847:2019 using the OpenSees software. Design of flat slab when using OpenSees software by creating the programming language will make it easy to analyze the structure of flat slab in other similar cases.Keywords: Drop panels, Flat slab, OpenSees, Punching shear, SNI 2847:2019 Issue No:Vol. 22, No. 2
Authors:Januarti Jaya ekaputri, Chikako Fujiyama, Nobuhiro Chijiwa, Benny Suryanto, Tu Dac Ho, Hung Thanh Nguyen Abstract: This paper presents the benefits of PVA fibers in improving the mechanical properties of class F fly-ash-based geopolymer concrete. The activator used in the geopolymer was 8M sodium hydroxide (NaOH) and sodium silicate (Na2SiO3), with a mass ratio of Na2SiO3 to NaOH varied from 1.5 to 2.5. Cylindrical specimens with a diameter of 100 mm and a height of 200 mm were prepared for mechanical strength tests. The PVA fibers in the geopolymers were fixed at 0.4%, 0.6%, and 0.8% by total volume. Some mechanical tests were carried out, including compression, splitting, direct tensile and elastic modulus tests. It was found that the mixture with a ratio of alkalis of 1.5 and the PVA fiber content of 0.4% had the best workability. The highest compressive strength was obtained in a mixture with alkali activator ratios of 1.5 and 2.0, and with 0.6% fiber addition. The ratio of the tensile (and splitting-tensile) strength to compressive strength was found to increase with the certain amount of PVA fibers and the ratio of the alkali activators. The workability issue and fiber direction in the concrete were the dominant factors influencing the properties of geopolymer concrete. Issue No:Vol. 22, No. 2
Authors:Adekemi Loretta AYODELE, Adefemi Daniel Adekoya, Abdulhalim Oshioke Mohammed, Ayowande Oluwatosin Abstract: This study investigates the use of phosphoric acid (H3PO4) and lime in stabilizing lateritic soil for lateritic bricks production. Varying percentages (0, 2, 4 and 6%) of 1 M H3PO4, 5% lime and their combinations were mixed with lateritic soil for stabilization purpose. Hollow bricks were produced from the different mixes. The bricks were cured for 7, 14 and 28 days under ambient air condition. The compressive strength (fc), bulk density (pb), dry density (pd) and water absorption rate were determined at each of the curing days while the modulus of rupture (fr) and pH were determined after 28 days. The results show a maximum fc of 0.93 N/mm2 and 0.87 N/mm2 were obtained at 5% and 4% H3PO4 stabilization. The maximum pb and pd of 15.2 kN/m3 and 14.9 kN/m3 respectively were obtained at 4% H3PO4 stabilization. The maximum fr of 0.2 N/mm2 was obtained at combined 4% H3PO4 and 5% lime stabilization while none of the bricks passed the water absorption test. Issue No:Vol. 22, No. 2
Authors:Godwin Ehis Oseghale, Johnson Damilola Adetooto, Bridget Ovbokhan Oseghale Abstract: The study appraised the degree of necessity and usage of material management methods adopted by small-scale construction firms in Abuja and Lagos State, Nigeria. It identified and examined the factors affecting material management practices, and assessed material management-related factors influencing cost variance. Eighty (80) structured questionnaire was administered on sites supervisor/manager through purposive sampling. Data obtained were analyzed using frequency, percentages, Mean score and relative severity index. The study revealed the most important material management method as site planning and organization (4.95), while employment of security (4.88) was often adopted for effective material management. The study found the most severe factors affecting material management as poor site organization, non-availability of material on sites, material not delivered as per schedule with severity index of (0.958), (0.948) and (0.928) respectively. Inadequate storage facilities (3.69), damaged materials (3.65), Loss of material (3.54), were found as material management factors most influencing cost variance. Issue No:Vol. 22, No. 2
Authors:Alireza Safari, Omid Rezaifar, Majid Gholhaki Abstract: Due to the importance of inventing new techniques capable of enhancing concrete structural properties while reducing environmental issues associated with CO2 emissions in concrete industry, which preoccupies environmental scientists, a novel investigation was performed as to feasibility of benefitting from Alternating Magnetic Field (AMF) and silica particles in order to attain this goal. Hence, some experiments were conducted on cylindrical concrete specimens comprising different percentages of silica sand up to 10%, wherein the influence of exposing ready mixed and hardened concrete to AMF of frequency 50Hz and density 0.5 Tesla (T) on compressive strength of 7 and 28-day specimens was evaluated. For this purpose, a specialized test setup was assembled in a way that the specimen could be subjected to compressive force and AMF, simultaneously. It was found that AMF can improve concrete compressive strength, where this technique is more efficient as to exposing hardened concrete. What was significant about the results was the fact that adding silica sand not only improved concrete mechanical strength, but also considerably enhanced the effectiveness of AMF in increasing concrete compressive strength, when applied to hardened concrete. For instance, replacing 10% of cement content with silica sand increased compressive strength of 28-day specimens by 8.4, but adding 10% silica sand along with exposing specimens to AMF yielded an increase of nearly 21% in real time. Thus, developing this method can result in a new generation of smart constructions. Moreover, by adding 10% silica sand the emission of carbon dioxide, a greenhouse gas, reduces by 10 percent, while significantly enhancing compressive strength. Issue No:Vol. 22, No. 2
Authors:Rian Mantasa Salve Prastica, Mochammad Anwar Najmi Shulthony, Annisa Putri Kinanti, Aryanti Karlina Nurendyastuti, Miftahul Jannah Abstract: Water-related disaster is widely happened including Indonesia. According to recent news, a watershed in South Sumatera got flooded due to heavy rainfall and other factors. The study focuses on Musi River, Palembang. The flood mitigation in Musi River system is studied with two alternatives, hydraulics modification and rainwater harvesting method. The research methodology of the paper covers hydrological analysis, hydraulics and slope stability calculation, 1-D HEC-RAS and Geo-Studio modelling, and rainwater harvesting analysis. The hydraulics modification seems able to reduce the flood in the watershed with 100% reduction meanwhile rainwater harvesting installation provides less promising flood mitigation due to only 1.71% water volume degradation in the study area. Issue No:Vol. 22, No. 2
Authors:OLANIYAN Olatunji Sunday Abstract: Modeling of sediment transport can be used to solve environmental and water quality problems. Sediment transport rate hinge upon hydraulic flow, upstream sediment supply and bed composition. River Osun is a river in southwestern of Nigerian that is ascribe in local mythology to have a woman turn into flowing water after a traumatic event. There is paucity of information on sediment transport dynamics of the riverHydrological and geometrical data were measured for 12 months at four sampling stations across River Osun. Stage and discharge rating equation was developed, the developed rating equation was used to predict discharge Schoklitsch’s (1950) equation and equation developed by USACE (1995) and Ongley (1996) were used to estimate unmeasured and measured load, respectively. However, comparison was made between Meyer Peter’s (1951) equation, Schoklitsch’s (1950) equation, Nielsen’s (1992) equation and Einstein’s (1950) equation results.The slope, discharge, flow area and Suspended Sediment Concentration (SSC) ranged between (0.0032-0.0046), (0.53-17.48)m3/s, (3.83-47.46)m2 and (10-175)mg/l, respectively. The average median grain size was 2.4mm. The seasonal suspended and bed load across River Osun were 206.43x103kg/annum and 2,538.77x103 kg/annum, respectively. The total sediment load on River Osun was 9,512.72x103 seasonal kg/annum. The coefficient of regression of 78% was obtained between the simulated and measured discharge values. Considering the quantity of sediment load computed on River Osun, preventive measure should be taken by the appropriate authority to reduce the sedimentation in River Osun. Issue No:Vol. 22, No. 2
Authors:Ofonime Akpan Harry Abstract: One of the ways of reducing the over dependent on river sand as fine aggregate is by using alternative materials. This study investigated the use of iron filling and glass particles as partial replacement for fine aggregate in concrete production. Percentages of iron filling and glass particle considered in the study were 0, 5, 10, 15, 20 and 25%. For each percentage considered, Compressive strength at 7, 14 and 28 days; and flexural strength at 28 days were determined. The result showed that compressive strength slightly increased with increase in percentage replacement of iron filling and glass particles up to 20%. Flexural strength of concrete increased with increase in percentage of iron filling and glass particle although the maximum flexural strength of 8.06N/mm2 and 7.17N/mm2 occurred at 15% replacement in concrete with iron filling and 25% in concrete with glass particle respectively. Issue No:Vol. 22, No. 2
Authors:Asdam Tambusay, Benny Suryanto, Priyo Suptobo Pages: 6 - 12 Abstract: This paper presents the application of a low-cost digital image correlation (DIC) system for automated crack mapping. The system employed makes use of a conventional digital camera, a remote image recording controller, and an open-source digital image correlation MATLAB software Ncorr. To showcase the potential of the proposed system, two case studies involving general structural and material testing were undertaken. In the first series, the DIC system was used to study the fracture processes in a reinforced concrete beam and to investigate the influence of key input parameters on the spatial quality of strain maps obtained from the DIC analysis. In the second series, the application of the DIC method was expanded to assist in the study of complex multiple micro-crack formations in ductile cement composite testing. It is shown that the strain maps obtained from the DIC technique have a close resemblance to the actual crack patterns DOI: 10.9744/ced.21.2.6-12 Issue No:Vol. 22, No. 2
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