JournalTOCs

Asian Journal of Civil Engineering
Number of Followers: 1

Hybrid journal (It can contain Open Access articles)
ISSN (Print) 1563-0854 - ISSN (Online) 2522-011X
Published by Springer-Verlag

[2626 journals]

Influence of reactive SiO 2 and Al 2 O 3 on mechanical and durability
properties of geopolymers
- Abstract: Abstract The various environmental ill effects from manufacturing of cement have provoked research into the advancement of concrete using a 100% replacement material by activated alkali solutions. Geopolymer concrete is an eco-friendly binder, which has attained significant attention among the researchers worldwide in past few decades. Large quantity of industrial waste ash is generated by thermal power plant, mining industry, timber industry, rice milling industry, steel and iron industry, etc. which have posed the industries a great threat when it comes to the disposal of these waste ash due to the various ill effects on health, environment, scarcity of lands, and other challenging issues. The best way in overcoming these waste management problems can be reduced by implementing geopolymer technology. The fundamental parameter in deciding the potential adoption of eco-friendly concrete in the construction sector is the durability of the construction material. This present study evaluates the influence of reactive silica/alumina present in the normal fly ash, ultra-fine fly ash, and ultra-fine slag, and blends of ultra-fine fly ash and ultra-fine slag on the strength development and durability properties. Test results indicate that the geopolymer concrete (GPC) exhibited high compressive strength and better durability characteristics when ultra-fine fly ash and slag are blended in optimum ratios to obtain a certain reactive silica/alumina ratio.
  PubDate: 2019-12-01
Fragility curves for steel–concrete composite shear wall building
with torsional irregularity
- Abstract: Abstract In this study, building model which is trapezoidal in plan with steel–concrete composite shear walls (SCCMSWs) is reduced to 1/4th scale in order to validate modal information and joint responses analytical results with AZALEE shake table under the scope of the SMART program. Incremental dynamic analysis (IDA) is performed on numerical model, and the maximum inter-storey drift is determined as a response parameter for all simulations. Fourteen real ground motion records are used to study the ground motion variability. Further, seismic fragility curves are developed based on IDA results to assess uncertainties in hazard evaluation of structure. Damage probability matrices under various damage states obtained from fragility curves are compared for building as per pre-established damage indicators of SMART 2008 and HAZUS 2003 specifications. It is concluded that, SCCMSWs building structure considered in the study behaves well when subjected to severe earthquakes.
  PubDate: 2019-12-01
Reactive project scheduling: minimizing delays in the completion times of
projects
- Abstract: Abstract Projects are delayed due to so many reasons. Salient amongst these reasons, in our opinion, is lack of proper planning before the commencement of the project. Many methods exist for the minimization of the completion times of projects. Some methods formulate the problem as resource-constrained project-scheduling problems (RCPSPs) and minimization of project completion time as objective. They find the minimal schedule that minimizes the total completion time of a project while satisfying the precedence and the resource constraints. The basic RCPSP assumes that the renewable resources are periodically renewed and their limited amount can vary from one period to another. The variability of available resource reflects real-life situations. Therefore, with added assumptions to the basic RCPSP, this work proposes a model called hybrid-RCPSP to solve delays in projects. Experimentally, two project examples were used to validate our solution method and it was shown that no matter how small the provided amount for each period, the projects were not unnecessarily delayed.
  PubDate: 2019-12-01
Evaluation and comparison of GFRP casing and CFRP sheets application on
the behavior of circular reinforced concrete column made of high-strength
concrete
- Abstract: Abstract This paper presents the results of axial compression testing on reinforced concrete columns (RCC) made with high-strength concrete (HSC) and confined by glass fiber-reinforced plastic (GFRP) casing and carbon fiber-reinforced polymer (CFRP). The major parameters evaluated in the experiments were the effects of GFRP casing, CFRP wrapping, and the number of CFRP layers. In this study, six cylindrical HSC-reinforced concrete columns (150 mm diameter and 600 mm height) were prepared and divided into two groups; with and without GFRP casing. In each group, one column was without CFRP, a column was wrapped with one CFRP layer, and another column with two CFRP layers. Concrete compressive strength was 63.1 MPa. All columns were tested under concentrated compression load. Results indicated that the utilization of CFRP wrapping and GFRP casing improved compression capacity and ductility of reinforced concrete columns. The addition of one and two CFRP layer wrapping increased compression capacity to an average of 10.2% and 24.8%, respectively; while the utilization of GFRP casing increased the compression capacity of the HSC columns by 3.38 times. These results indicate that although both CFRP wrapping and GFRP casing resulted in confinement, the GFRP casing has a higher effect on increased compression capacity.
  PubDate: 2019-12-01
An overview of long-span spatial grid structures failure case studies
- Abstract: Abstract This paper provides insights on seven case failure studies for long-span hangars from 2004 to 2017 from different regions with unique failure factors leading to distress, partial or total collapse. A brief description of the cases studied entails project nature, and general technical and non-technical issues causing the hangar failures. A two-way approach (before and after collapse) features all the cases through commissions of inquiry and forensic studies done through fieldwork investigations, sensitivity, reliability, strength, capacity, and durability analysis. The cases studied were acted upon by static loads, and 83% of the failures occurred during service stage. The failures are as a result of human errors in design and calculations, ignorance of construction stages stakeholders leading to causative factors, stresses during erection and assembly process, randomness in loading and boundary conditions, over-reliance of computer analysis with no confirmation from a third-party analysis, under-estimation of member geometric and nodal imperfections primarily through joint rotations and members lack of fit, and manufacturing errors leading to residual stresses on the members. Achieve a preventive failure measure, detect design errors, and give comprehensive part details and construction stages, and analyze spatial grid structures with the correct boundary conditions to take advantage of support and joint stiffness. Utilize ductility and structural efficiency of under-stressed members, reinforce adjacent members on overstressed areas and conduct loading and unloading tests. Apply all loads, ventilation, and lighting fittings only at the joints to avoid load eccentricity. All the case studies are referenced from their principal sources and reports.
  PubDate: 2019-12-01
Infiltration and clogging characteristics of pervious concrete
- Abstract: Abstract Pervious concrete is essentially used to reduce stormwater runoff and local floods. It requires regular maintenance because it is highly prone to clogging by particulate matters. Clogging is defined as a reduction in hydraulic conductivity that drastically reduces the permeability into the subgrade. A study using permeability as a key parameter was carried out to measure the infiltration characteristics of pervious concrete containing various binders and different sizes of coarse aggregates namely 6.3 mm, 8 mm, 10 mm and 12.5 mm. The binders such as Ordinary Portland Cement (OPC), Portland Pozzolana Cement (PPC), Fly ash based Geopolymer (GP) and Fly ash—Lime-Gypsum (FaL-G) were used. The results indicated that pervious concrete made with aforesaid binders showcased adequate infiltration properties that satisfied the requirements of pervious concrete. Furthermore, clogging effect study was performed in GP binder pervious concrete by applying flowing water containing mud to determine worst-case scenario percentage for clogging. The worst-case silt percentage in water to cause clogging was found to be 8.26%, 9.21%, 9.84% and 10.16%. The test results indicated that increasing of clogging material in the water significantly reduces the permeability.
  PubDate: 2019-12-01
Prevention of crack formation in massive concrete at an early age by
cooling pipe system
- Abstract: Abstract Cooling pipe system (CPS) in concrete arrays plays an important role to control the temperature changes in massive concrete such as dams, foundation bridges, etc. The application of CPS in massive concrete has also been studied by some researchers but only in positive qualities point of view of the CPS. The present study presents the results of an investigation of thermal behavior regarding crack formation due to the hydration heat in massive concrete structures. To reduce the thermal load and improve the reliability of protection against cracks in massive concrete, the temperature changes, particularly the temperature field and thermal stress, in such concrete with the presence of CPS were simulated and calculated with the help of the advanced computer programs. In addition, both the temperature field and the cracking index in the massive concrete with the CPS’s temperature of 15 °C were determined. As the results, the cracking index over time was greater than the allowable value of 1.5, which indicates that the risk of cracking did not occur when the CPS was applied in the massive concrete.
  PubDate: 2019-12-01
Comparative study of effect of web openings on the strength capacities of
steel beam with trapezoidally corrugated web
- Abstract: Abstract In steel I beams the corrugated webs are sometimes used as an alternative to plain web in many steel construction. The idea behind this concept is an increase in the shear capacity of steel beams without providing the transverse stiffeners. The recent development in steel construction is the used of web openings for the utilization of various technical utilities in web. This paper presents an extensive parametric study on the steel beam with corrugated web having openings in the web. The objective of the present study is to observe the structural performance of this special type of beam towards the strength capacities. In the parametric study 60 models of steel beams with trapezoidally corrugated web with opening has been analyzed by finite element analysis using ANSYS v12. The variables in the present study are angle of corrugation, thickness of web and diameter of opening. The angle of corrugation, web thickness and diameter of web openings considered in the study are 0°, 30°, 45° and 3 mm, 4 mm, 5 mm and 0.5, 0.6, 0.75 times the overall depth of beam, respectively. The parametric study shows that lesser the angle of web corrugation, the more increase in the load carrying capacity is obtained. Ultimate strength capacity of 30° corrugated web beam with different diameter of opening such as 0.5 D, 0.6 D, and 0.75 D is found to be 15.27%, 14.83%, 9.72%, which is more than the beam with plain web. The height to thickness (h/tw) ratio considered in the study are 30, 37.5, 40, 50, and 66.67, respectively. The height to thickness (h/tw) ratio is found to be the main parameter influencing the buckling behaviour of steel beam with corrugated web.
  PubDate: 2019-12-01
Effects of CFRP/GFRP flexural retrofitting on reducing seismic damage of
reinforced concrete frames: a comparative study
- Abstract: Abstract Flexural retrofitting of structures using glass/carbon fibre reinforced polymer (GFRP/CFRP) has been widely investigated. However, comparison on the effects of GFRP/CFRP flexural retrofitting at plastic hinges on reducing the potential seismic damage of reinforced concrete (RC) structures is hardly found in the literature and is thus aimed by this study. Toward this aim, two-, four- and eight-storey RC frames were chosen to represent different building structures. These frames were then retrofitted by CFRP/GFRP bonded sheets to increase flexural capacities of beams and columns at plastic hinge regions. The original, CFRP and GFRP retrofitted frames were modelled using nonlinear hysteresis elements. After verification, nonlinear time-history analyses of those frames under various seismic intensities were carried out, followed by cumulative damage analyses. Damage states of original, CFRP and GFRP retrofitted frames were compared with one another. The obtained comparison results reaffirmed the effectiveness of CFRP and GFRP flexural retrofitting. More importantly, obtained results indicated that CFRP is more effective than GFRP on reducing seismic damage of RC structures when they are employed for flexural retrofitting. These outcomes can help in deciding on the FRP type to be used for flexural retrofitting of RC structures.
  PubDate: 2019-12-01
Mixing of dredging sludge with EPS beads and cement paste in continuous
M–Y mixer
- Abstract: Abstract The 2n mixing theory was developed with the concept of Japanese noodle (UDON) making method. The mixing of dredging sludge was done with 20% (by volume) of expanded-poly-styrene beads in 15 units of M–Y Mixer using the cement paste. Samples were taken at starting, middle and end level of continuous mixing. Average unit weight was 1.07 gm/cm3, with its variation coefficient of 2.68%. Average 28 days compressive strength was 7.04 MPa, with a variation coefficient of 3.66%. The efficiency of the M–Y mixer was sufficient for continuous mixing of dredging sludge, giving required compressive strength for soil settlement.
  PubDate: 2019-12-01
Comparative study of effect hot climate and conventional water on strength
development of SFR-SCMs using natural pozzolana replacement
- Abstract: Abstract The present paper intends to study the influence of hot climate curing on strengths development of sisal fiber-reinforced self-compacting mortars (SFR-SCMs), with a view to repairing concrete structures. Hot climate environment was compared to conventional water curing in a period up to 56 days. Five SFR-SCMs mixes containing 0%, 10%, 20%, 30%, and 40% of natural pozzolana (NP) as Portland cement (CEMII/A-L 42.5 N) replacement were made and then subjected to these curing environments. In addition, for curing durations of 2–7, all samples cured via hot climate were sprayed with fresh water twice a day. The obtained results encourage the use of the spraying method, because it was effective to counteract the detrimental effect of hot climate on continuation of hydration and strength development, which allowed to reach the minimum required 28-day strength for class R3, repair materials (EN 1504-3). However, samples containing up to 20% NP cured under conventional water reached the minimum required 28-day strength for class R4. For curing durations of 28–56 days, the compressive strength of specimens cured via conventional water increased considerably due to the pozzolanic reactions, but, that of samples cured via hot climate, slightly decreased due to moisture loss. Furthermore, a regression analysis was performed to establish a mathematical relationship between flexural and compressive strengths of SFR-SCMs. Study results indicate that the coefficient of determination (R2) may reach 0.90, indicating that the proposed method is suitable for predicting flexural strength from compressive strength, under the chosen curing environments.
  PubDate: 2019-12-01
Determination of compressive strength using relevance vector machine and
emotional neural network
- Abstract: Abstract Compressive strength is an important and pertinent property for the characterization of concrete. It is known that compressive strength of hardened concrete depends on the efficiency factor (K) of silica fume and its percentage replacement (%SF). Consequently, the ultrasonic pulse velocity (UPV) is also an important factor for predicting compressive strength. The article examines the capability of relevance vector machine (RVM) and emotional neural network (ENN) for determination of compressive strength using the efficiency factor, percentage silica fume replacement and UPV as an input parameter. A comparative study has been carried out for the developed model using RVM and ENN. The analysis confirms that both RVM and ENN are a robust model for the prediction of compressive strength of hardened concrete.
  PubDate: 2019-12-01
Confinement effects on circular steel tubes filled with foamed concrete
(FCFST) subjected to axial thrust and bending
- Abstract: Abstract This paper presents an experimental investigation on the confinement effects of circular steel tubes filled with foamed concrete (FCFST) subjected to axial thrust and bending. The application of the concrete filled steel tube column as a structural element has increased substantially lately. A series of experimental investigations was conducted on circular steel hollow tubes filled with foamed concrete (FCFST) to inspect the confinement effects between steel tube and foamed concrete and to estimate the optimum axial and flexural capacities of steel tube columns filled with foamed concrete. Twenty (20) numbers of column specimens of circular sections were tested up to failure under axial compressive loading and bending. Various parameters such as the optimum strength of the FCFST, load–deflection, mode of failure and confinement effects were measured and observed. The results of the experimental investigation showed that although the maximum axial capacities of composite stub column specimens were lower than the calculated theoretical values of the squash load (BS5400, Mander and ACI), complete stub column behavior can still be observed on these column specimens. As the density of foamed concrete column increases (from 800 to 1600 kg/m3), there is an apparent quite-significant drop in the lower (percentage) squash load of the experimental value compared to the average theoretical values (from 17 to 14%). Meanwhile, slender column specimens produced significant value of moments when compared with values obtained via analytical consideration (BS5400).
  PubDate: 2019-11-01
Assessment of the fundamental natural frequency of bridge decks
- Abstract: Abstract In this paper, considering some important and influencing parameters on the fundamental natural frequencies of bridges including bridge span length, number of spans, bridge width, number of girders, and height of girders, variation of the fundamental natural frequency of the first bending mode of typical bridge superstructures in terms of each of the aforementioned parameters were assessed. According to the results, the first bending frequency of bridge decks is reversely related to the span length and directly related to the number of spans and the bridge width. It should be noted that the effect of other assumed parameters such as the height and number of girders is indirectly applied to the number of spans and bridge width, and can be neglected as independent parameters affecting the natural frequency of the first bending mode.
  PubDate: 2019-11-01
Seismic evaluation of reinforced concrete structures infilled with masonry
infill walls
- Abstract: Abstract The current research work aims to investigate the seismic performance of the reinforced concrete structures fully, as well as, partially infilled with masonry infill (MI) walls. For that, a numerical study of three groups of two-dimensional framed structure has been conducted under dynamic time–history analysis. The three building groups are classified as nine, six and three stories representing high-rise building, medium-rise building, and low-rise building, respectively. Different infill walls’ configurations have been studied for each group to simulate the bare frame, the infilled frame, the open ground story frame, and the partially opened ground story frame. Double-strut nonlinear cyclic model for MI walls has been utilized to represent nonlinear behavior of infill walls in the framed structures using the structural software package SeismoStruct software. Dynamic time–history analysis, using three different ground motion records to represent wide range of frequency content, has been utilized to study the performance of the studied cases under seismic loading conditions. Based on the obtained results, the seismic performance of the framed structures is strongly influenced after using the infill walls. However, removing the MI walls from the ground story leads to soft story phenomena and makes the structures vulnerable to collapse especially in moderate-to-severe earthquakes.
  PubDate: 2019-11-01
A simplified frequency formula for post-tensioned balanced cantilever
bridges
- Abstract: Abstract The aim of this study is to develop a simplified natural fundamental frequency formula for the post-tensioned balanced cantilever bridges using the Operational Modal and Finite Element Analyses results. For this purpose, experimental and numerical studies were carried out on the five post-tensioned balanced cantilever bridges constructed in the city of Artvin, Turkey. First, the experimental and theoretical dynamic characteristics of the selected five bridges were determined using the ambient vibration-based Operational Modal Analysis and Finite Element Method, respectively. Then, the bridge model, which is given the highest correlation between the experimental and theoretical frequencies, was selected to determine the most important parameters that affected the modal behavior of the bridges. The most important parameters were determined as bridge length and pier height. Theoretical modal analyses were carried out for a series of bridge models with different lengths and heights. Finally, a simplified fundamental frequency formula was developed for the post-tensioned balanced cantilever bridges using the method of least squares considering the frequency values obtained from the theoretical modal analyses of the bridge models. The developed formula was checked with the experimentally obtained values, and it was observed that both sets of results were close to each other.
  PubDate: 2019-11-01
Modelling construction completion cost in Ghana public sector building
projects
- Abstract: Abstract The research suggests that project completion cost is affected by various predictive factors. Using 911 building projects undertaken in Ghana, this paper uses the multiple regression analysis to develop a forecast model that allows estimating completion cost of projects at the contract award stage. The proposed model uses initial contract sum, number of storeys, scope change and initial duration as predictive variables for projects completion cost. Initial contract sum has a more significant influence in completion cost with the other variable also contributing to the value of completion. Sensitivity analysis was carried out to determine the best performing model among the three models developed.
  PubDate: 2019-11-01
Optimal reliability design of pure friction isolators using asymptotic
sampling
- Abstract: Abstract Probabilistic methods are widely being used in structural design due to the vital effects on the structural safety prediction. In the present study, reliability-based analysis of a shear frame supported on pure friction base isolators equipped with a restoring device is performed and changing of friction coefficient of the base isolator, the mass of the base raft ratio and the damping ratio of the restoring device are investigated. The earthquake herein is treated as a non-stationary random process. The probability of failure is computed using first-passage probability which is determined utilizing a new sampling technique called asymptotic sampling. This study introduces the safe range for each variable on the design space based on reliability indices. The assessment is done for different circumstances in which there are one determined variable and two uncertain. In each circumstance, a Pareto-type optimization is done in order to achieve the optimum design variables. Finally, a total optimization is done for all three design variables to determine the optimum values. Moreover, the reliability analysis of the isolated frame without a restoring device is conducted to show the substantial impact of adding the restoring device to the isolator by achieving considerably higher safety indices.
  PubDate: 2019-11-01
Comparative assessment of the contending force and placement methods for
weightless sagging cables
- Abstract: Abstract Sagging elastic cables are inherently nonlinear structures due to the presence of self-weight apart from the presence of conventional physical and geometrical nonlinearities. Recently, authors have proposed a force method of weightless sagging elastic cables with linear tension–extension relations and undergoing small elastic displacements to focus explicitly on their characteristic ‘configurational’ nonlinearity. This force method is based upon the rate-type constitutive equations and third-order differential equations of motion. Existing displacement method is reconstructed here for the physically linear weightless sagging elastic cables undergoing finite elastic displacements. In place of nodal forces in force method, deformed state nodal placements are the primary variables in this placement method. Rate-type constitutive equations for two-node weightless planar sagging elastic cables are derived. The objective of the present paper is to compare and contrast these two contending methods in reference to their underlying hypotheses, analytical reach, and quantitative predictions of structural response. Possible equivalence of the proposed third-order and the popular incremental second-order differential equation of motion are explored. Theoretical significance of the present paper is critically evaluated.
  PubDate: 2019-11-01
Algerian seismic code improvement by proposition of a specific design
spectrum for Algiers City
- Abstract: Abstract This paper is an involvement in the improvement of the Algerian seismic regulation (RPA) which presents many deficiencies. Investigations are focused on the so-called “spectral modal analysis” (SMA) method commonly used for seismic evaluation. The applications are made on reinforced concrete structures in both cases: self-steady frames and structures with shear walls (bearing walls). Furthermore, comparison is made with time history (TH) method based on a number of recent Algerian seismic records. This work led to the proposition of a more accurate design spectrum specific to Algiers City usable in the classical (force) method as well as in a simplified “performance-based” method.
  PubDate: 2019-11-01