Advances in Civil Engineering The latest articles from Hindawi © 2017 , Hindawi Limited . All rights reserved. 4D Applications of GIS in Construction Management Mon, 22 May 2017 00:00:00 +0000 Construction industries broadly involve different set of construction activities which are to be executed as per schedule and the major software used for scheduling is PRIMAVERA and Microsoft Project (MSP). But the software still lacks a feature of providing spatial aspects of information in construction schedule. Recently, advanced technology like 4D GIS plays a major role in overcoming the limitation of the software. 4D GIS technology includes integration of 2D drawings from AutoCAD and schedules prepared in PRIMAVERA software. In the present study, a multistair residential building has been selected. ARCMAP 10.2 is used for interlinking of schedules as well as drawings and ARCSCENE has been used for developing 4D view. This linkage between scheduled activities and respective drawings in GIS helps in identifying construction sequences and also in detecting logical errors that occur in project schedules. The developed 4D view provides better visualization of construction progress of a project. A. Chaitanya Kumar and T. Reshma Copyright © 2017 A. Chaitanya Kumar and T. Reshma. All rights reserved. Experimental Research and Finite Element Analysis on Mechanical Property of SFRC T-Beam Thu, 04 May 2017 09:26:39 +0000 Research on mechanical property of SFRC was done through experiments of two SFRC T-beams and one concrete T-beam, while the influences of different volume fractions of steel fibers on integral rigidity, ultimate shear capacity, and the crack distribution characteristics were analyzed. ANSYS finite element software was used to simulate the tests and it was found that there was good conformation between the results of ANSYS simulation and tests. The test results and finite element software simulation both showed that the incorporation of steel fibers in the concrete can increase the integral rigidity and ultimate shear capacity, while partially reducing the propagation of cracks effectively. It was also proved that it is reliable to simulate SFRC T-beam by ANSYS software. Min Sun, Jiapeng Zhu, Ning Li, and C. C. Fu Copyright © 2017 Min Sun et al. All rights reserved. Numerical Simulations of Restrained Shrinkage Cracking in Glass Fibre Reinforced Shotcrete Slabs Wed, 03 May 2017 06:56:55 +0000 Modern tunnels in hard rock are usually constructed by drill and blast with the rock reinforced by shotcrete (sprayed concrete) in combination with rock bolts. The irregular rock surface and the projection method of shotcrete lead to a tunnel lining of varying thickness with unevenly distributed stresses that affect the risk of cracking during shrinkage of the young and hardening material. Depending on water conditions, shotcrete is sprayed directly either onto the rock surface or over a drainage system, creating a fully restrained or an end-restrained structural system. In this paper, a method for nonlinear numerical simulations has been demonstrated, for the study of differences in stress build-up and cracking behaviour of restrained shotcrete slabs subjected to shrinkage. Special focus was given to the effects of the irregular shape and varying thickness of the shotcrete. The effects of glass fibre reinforcement and bond were implemented in the study by changing the fracture energy in bending and in the interaction between shotcrete and the substrate. The study verifies that an end-restrained shotcrete slab is prone to shrinkage induced cracking and shows the importance of a continuous bond to avoid wide shrinkage cracks when shotcrete is sprayed directly onto the rock. Andreas Sjölander and Anders Ansell Copyright © 2017 Andreas Sjölander and Anders Ansell. All rights reserved. Influence of Crumb-Rubber in the Mechanical Response of Modified Portland Cement Concrete Tue, 02 May 2017 09:51:27 +0000 The influence of crumb-rubber on the mechanical properties of Portland cement concrete (PCC) is studied by experimental tests and numerical simulations. The main hypothesis of the study is that replacing part of the stone aggregate with crumb-rubber in the mix modifies the energy dissipation during the cracking process and affects the concrete behaviour under monotonically increasing loads. The experimental research program characterizes the mechanical properties of PCC for three different types of concrete with a variable content of crumb-rubber. The experimental results showed that fracture energy and other properties are directly related to the rubber fineness used in the mixture. The material properties derived for these laboratory tests are used to study, by numerical models, its response through its damage evolution. The numerical model used to simulate the damage evolution of the concrete is the Embedded Discontinuity Method (EDM). One characteristic of the EDM is that it does not need to modify the mesh topology to propagate the damage through the continuum solid. For this study, the Disk-Shaped Compact Tension specimen geometry, normed by the D7313-13 of the ASTM, is used. Results showed that the numerical methods provide good approximation of the experimental curve in the elastic and softening branches. J. Retama and A. G. Ayala Copyright © 2017 J. Retama and A. G. Ayala. All rights reserved. Design Diagrams for the Analysis of Active Pressure on Retaining Walls with the Effect of Line Surcharge Tue, 02 May 2017 08:42:42 +0000 In this study, a formulation has been proposed to calculate the pressure on wall and determine the angle of failure wedge based on limit equilibrium method. The mentioned formulation is capable of calculating active pressure coefficient, culmination of forces in failure surface, and pressure distribution on wall with the effect of line surcharge. In addition, based on the proposed method, a simple formula has been proposed to calculate the angle of failure wedge by the effect of surcharge. Moreover, the proposed approach has the advantage of taking into account the effect of surcharge on elastoplastic environment by considering the parameters of soil and determining the extent to which the surcharge is effective in pressure distribution on the wall. However, in most previous methods and specifications, resultant lateral pressure from surcharge in elastic environment had been considered. Finally, based on the obtained results, the design diagrams for different soils and different surcharges have been proposed. According to these diagrams, pressure on wall, pressure distribution on wall, and angle of failure wedge will easily be achieved. Also, a computer program has been written in MATLAB software environment. Using the results of these codes, the pressure on wall with the effect of surcharge, the angle of failure wedge, and pressure distribution on wall will be determined. Mojtaba Ahmadabadi and Mohammad Karim Faghirizadeh Copyright © 2017 Mojtaba Ahmadabadi and Mohammad Karim Faghirizadeh. All rights reserved. Bond Effects between Concrete and Steel Bar Using Different Diameter Bars and Different Initial Crack Width Sun, 02 Apr 2017 08:08:37 +0000 The importance of an accurate simulation of service conditions in the bond performance of reinforced concrete structures in coastal regions is highlighted. Four widths of initial crack of 0, 80, 150, and 210 microns were artificially made by inserting slice into bond specimens during concrete casting. Three bar diameters of 10 mm, 14 mm, and 18 mm were selected. At 28 days, the bond specimens were exposed to the environment of wet-dry cycles of seawater and atmosphere for another 90 days. The pull-out test was then conducted and chloride contents were tested at crack area along 40 mm depth. Results show that, for the specimen with 10 mm bar diameter, cracks width of less than 80 microns vanished rapidly during wet-dry cycles; for other specimens, cracks width of 100–150 microns decreased slightly. However the cracks of width more than 200 microns increased gradually; the chloride content decreased along the depth of concrete, and the chloride content increased as the widths of initial cracks increased or as the bar diameters increased. The ductility of bond specimens decreased as the diameter increased. Papa Niane Faye, Yinghua Ye, and Bo Diao Copyright © 2017 Papa Niane Faye et al. All rights reserved. Experimental Studies on Punching Shear and Impact Resistance of Steel Fibre Reinforced Slag Based Geopolymer Concrete Wed, 22 Mar 2017 08:29:28 +0000 The study was focused on slag based geopolymer concrete with the addition of steel fibre. The slag based geopolymer concrete was under shear load and sudden impact load to determine its response. The punching shear represents the load dissipation of the material and the energy absorption capacity of the geopolymer concrete to impact load. The various percentage of steel fibre in the slag based geopolymer concrete was 0.5%, 1.0%, and 1.5%. Overall the dosage 0.5% of steel fibre reinforced slag based geopolymer shows better results with a punching shear of 224 kN and 1.0% of steel fibre incorporated geopolymer concrete had the better energy absorption capacity with 3774.40 N·m for first crack toughness and 4123.88 N·m for ultimate failure toughness. Srinivasan Karunanithi Copyright © 2017 Srinivasan Karunanithi. All rights reserved. Tests and Analyses of Slotted-In Steel-Plate Connections in Composite Timber Shear Wall Panels Mon, 20 Mar 2017 00:00:00 +0000 The authors present an experimental and analytical study of slotted-in connections for joining walls in the Masonite flexible building (MFB) system. These connections are used for splicing wall elements and for tying down uplifting forces and resisting horizontal shear forces in stabilizing walls. The connection plates are inserted in a perimeter slot in the PlyBoard™ panel (a composite laminated wood panel) and fixed mechanically with screw fasteners. The load-bearing capacity of the slotted-in connection is determined experimentally and derived analytically for different failure modes. The test results show ductile postpeak load-slip characteristics, indicating that a plastic design method can be applied to calculate the horizontal load-bearing capacity of this type of shear walls. Ulf Arne Girhammar and Bo Källsner Copyright © 2017 Ulf Arne Girhammar and Bo Källsner. All rights reserved. Behavior of Low Grade Steel Fiber Reinforced Concrete Made with Fresh and Recycled Brick Aggregates Thu, 16 Mar 2017 07:47:18 +0000 In recent years, recycled aggregates from construction and demolition waste (CDW) have been widely accepted in construction sectors as the replacement of coarse aggregate in order to minimize the excessive use of natural resources. In this paper, an experimental investigation is carried out to observe the influence of low grade steel fiber reinforcements on the stress-strain behavior of concrete made with recycled and fresh brick aggregates. In addition, compressive strength by destructive and nondestructive tests, splitting tensile strength, and Young’s modulus are determined. Hooked end steel wires with 50 mm of length and an aspect ratio of 55.6 are used as fiber reinforcements in a volume fraction of 0% (control case), 0.50%, and 1.00% in concrete mixes. The same gradation of aggregates and water-cement ratio () were used to assess the effect of steel fiber in all these concrete mixes. All tests were conducted at 7, 14, and 28 days to perceive the effect of age on different mechanical properties. The experimental results show that around 10%~15% and 40%~60% increase in 28 days compressive strength and tensile strength of steel fiber reinforced concrete, respectively, compared to those of the control case. It is observed that the effect of addition of 1% fiber on the concrete compressive strength is little compared to that of 0.5% steel fiber addition. On the other hand, strain of concrete at failure of steel fiber reinforced concrete has increased almost twice compared to the control case. A simple analytical model is also proposed to generate the ascending portions of the stress-strain curve of concrete. There exists a good correlation between the experimental results and the analytical model. A relatively ductile failure is observed for the concrete made with low grade steel fibers. Md. Shariful Islam and Mohammad Al Amin Siddique Copyright © 2017 Md. Shariful Islam and Mohammad Al Amin Siddique. All rights reserved. A Simplified Parametric Study on Occupant Comfort Conditions in Base Isolated Buildings under Wind Loading Sun, 19 Feb 2017 00:00:00 +0000 Vibrations in buildings can cause occupant discomfort in the form of annoyance, headache, or sickness. While occupant comfort is considered in international standards regarding the design of high rise buildings against wind loading, it is neglected in the design of buildings with seismic protective base isolation systems. Nevertheless, due to their low flexibility, base isolated buildings can be prone to wind-induced vibrations, which makes occupant discomfort a potentially significant serviceability limit state. This paper presents a study on occupant comfort conditions in wind-excited base isolated buildings. A numerical simplified parametric procedure is proposed in order to evaluate the return period of wind events causing human discomfort. A parametric investigation is then presented to evaluate the effects of salient parameters on comfort conditions. The procedure is based on (i) the nonlinear dynamic analysis of the structure modeled as a single-degree-of-freedom oscillator with hysteretic base isolators, (ii) the digital generation of time histories of turbulent wind velocity, and (iii) comfort evaluations based on international standards. Results demonstrate that discomfort conditions can occur a few times in a year, depending upon the wind-exposure of the site, what suggests considering this serviceability limit state in the design of base isolated buildings. F. Ubertini, F. Comodini, A. Fulco, and M. Mezzi Copyright © 2017 F. Ubertini et al. All rights reserved. Parameter Analysis on Wind-Induced Vibration of UHV Cross-Rope Suspension Tower-Line Thu, 16 Feb 2017 07:15:31 +0000 This paper analyzes the influences of important structural design parameters on the wind-induced response of cross-rope suspension tower-line. A finite element model of cross-rope suspension tower-line system is established, and the dynamic time-history analysis with harmonic wave superposition method is conducted. The two important structural design parameters such as initial guy pretension and sag-span ratio of suspension-rope are studied, as well as their influences on the three wind-induced vibration responses such as tensile force on guys, the reaction force on mast supports, and the along-wind displacement of the mast top; the results show that the value of sag-span ratio of suspension-rope should not be less than 1/9 and the value of guy pretension should be less than 30% of its design bearing capacity. On this occasion, the tension in guys and compression in masts would be maintained in smaller values, which can lead to a much more reasonable structure. Xilai Li, Dengke Yu, and Zhengliang Li Copyright © 2017 Xilai Li et al. All rights reserved. Moment-Curvature Behaviors of Concrete Beams Singly Reinforced by Steel-FRP Composite Bars Wed, 15 Feb 2017 07:56:42 +0000 A steel-fiber-reinforced polymer (FRP) composite bar (SFCB) is a kind of rebar with inner steel bar wrapped by FRP, which can achieve a better anticorrosion performance than that of ordinary steel bar. The high ultimate strength of FRP can also provide a significant increase in load bearing capacity. Based on the adequate simulation of the load-displacement behaviors of concrete beams reinforced by SFCBs, a parametric analysis of the moment-curvature behaviors of concrete beams that are singly reinforced by SFCB was conducted. The critical reinforcement ratio for differentiating the beam’s failure mode was presented, and the concept of the maximum possible peak curvature (MPPC) was proposed. After the ultimate curvature reached MPPC, it decreased with an increase in the postyield stiffness ratio (), and the theoretical calculation method about the curvatures before and after the MPPC was derived. The influence of the reinforcement ratio, effective depth, and FRP ultimate strain on the ultimate point was studied by the dimensionless moment and curvature. By calculating the envelope area under the moment-curvature curve, the energy ductility index can obtain a balance between the bearing capacity and the deformation ability. This paper can provide a reference for the design of concrete beams that are reinforced by SFCB or hybrid steel bar/FRP bar. Zeyang Sun, Yang Yang, Wenlong Yan, Gang Wu, and Xiaoyuan He Copyright © 2017 Zeyang Sun et al. All rights reserved. Effect of Modified Rubber Particles Mixing Amount on Properties of Cement Mortar Sun, 29 Jan 2017 06:25:51 +0000 The crumb rubber cement mortar is prepared by the crumb rubber aggregates in 60 mesh which are modified by 1% polyvinyl alcohol (PVA) solution. Some mechanical properties of cement mortar with different crumb rubber aggregate amounts are researched including compressive strength, flexural strength, the ratio of compressive strength to flexural strength, impact resistance, and dry contraction percentage. In our tests, we consider six kinds of the rubber contents, 0%, 7.5%, 15%, 19%, 22.5%, and 30%, respectively. The optimal mixing amount of crumb rubber is determined by measuring three indices, the ratio of compressive strength to flexural strength, impact resistance, and dry contraction percentage. It is shown by test that the ratio of compressive strength to flexural strength is the smallest when the mixing amount of rubber is 19%; meanwhile high impact resistance and rational drying shrinkage are observed. The optimal mixing amount of the rubber particles is 19% determined by this test. Gang Xue and Mei-ling Cao Copyright © 2017 Gang Xue and Mei-ling Cao. All rights reserved. Bond Strength between Hybrid Fiber-Reinforced Lightweight Aggregate Concrete Substrate and Self-Compacting Concrete as Topping Layer Mon, 23 Jan 2017 00:00:00 +0000 Structural performance evaluation of composite concrete slabs that were constructed using partially precast concreting system which utilized Hybrid Fiber-Reinforced Lightweight Aggregate Concrete (HyFRLWAC) as stay in-place formwork and self-compacting concrete (SCC) as topping layer was conducted in this research. This paper focused on determining the appropriate strength limit criteria of interface between two different concrete layers. The tensile strength was tested using pull-off test, while concrete cohesion was investigated based on modified bisurface shear test, and dual L-shaped shear test was used to determine the effect of normal force on the shear strength of concrete interface. Sample variants were designed based on the substrate surface conditions, compressive strength of the topping layer, and magnitude of perpendicular normal force acting on interface area. The substrate surfaces were prepared in as-placed and grooved conditions for tensile test, cohesion, and shear strength test. Test results indicate that tensile strength, cohesion, and shear strength of the concrete interface are affected by surface condition of the substrate, compressive strength of the topping layer, and the normal force acting perpendicularly on the concrete interface area. Proposed formulation for bond strength prediction between HyFRLWAC as substrate and SCC as topping layer is also presented in this paper. Slamet Widodo Copyright © 2017 Slamet Widodo. All rights reserved. Experimental Study on the Utilization of Fine Steel Slag on Stabilizing High Plastic Subgrade Soil Tue, 17 Jan 2017 00:00:00 +0000 The three major steel manufacturing factories in Jordan dump their byproduct, steel slag, randomly in open areas, which causes many environmental hazardous problems. This study intended to explore the effectiveness of using fine steel slag aggregate (FSSA) in improving the geotechnical properties of high plastic subgrade soil. First soil and fine steel slag mechanical and engineering properties were evaluating. Then 0%, 5%, 10%, 15%, 20%, and 25% dry weight of soil of fine steel slag (FSSA) were added and mixed into the prepared soil samples. The effectiveness of the FSSA was judged by the improvement in consistency limits, compaction, free swell, unconfined compression strength, and California bearing ratio (CBR). From the test results, it is observed that 20% FSSA additives will reduce plasticity index and free swell by 26.3% and 58.3%, respectively. Furthermore, 20% FSSA additives will increase the unconfined compressive strength, maximum dry density, and CBR value by 100%, 6.9%, and 154%. By conclusion FSSA had a positive effect on the geotechnical properties of the soil and it can be used as admixture in proving geotechnical characteristics of subgrade soil, not only solving the waste disposal problem. Hussien Aldeeky and Omar Al Hattamleh Copyright © 2017 Hussien Aldeeky and Omar Al Hattamleh. All rights reserved. Proposal of Design Formulae for Equivalent Elasticity of Masonry Structures Made with Bricks of Low Modulus Tue, 17 Jan 2017 00:00:00 +0000 Bricks of low elastic modulus are occasionally used in some developing countries, such as Indonesia and India. Most of the previous research efforts focused on masonry structures built with bricks of considerably high elastic modulus. The objective of this study is to quantify the equivalent elastic modulus of lower-stiffness masonry structures, when the mortar has a higher modulus of elasticity than the bricks, by employing finite element (FE) simulations and adopting the homogenization technique. The reported numerical simulations adopted the two-dimensional representative volume elements (RVEs) using quadrilateral elements with four nodes. The equivalent elastic moduli of composite elements with various bricks and mortar were quantified. The numerically estimated equivalent elastic moduli from the FE simulations were verified using previously established test data. Hence, a new simplified formula for the calculation of the equivalent modulus of elasticity of such masonry structures is proposed in the present study. Muhammad Ridwan, Isamu Yoshitake, and Ayman Y. Nassif Copyright © 2017 Muhammad Ridwan et al. All rights reserved. Series-Based Solution for Analysis of Simply Supported Rectangular Thin Plate with Internal Rigid Supports Wed, 04 Jan 2017 12:13:17 +0000 In this study, Navier’s solution for the analysis of simply supported rectangular plates is extended to consider rigid internal supports. The proposed method offers a more accurate solution for the bending moment at the critical section and therefore serves as a better analytical solution for design purposes. To model the plate-support interaction, the patched areas representing the contact between the plate and supports are divided into groups of cells. The unknown internal reactions at the centers of the divided cells are obtained by satisfying the compatibility conditions at the centers of the cells. Three numerical examples are presented to demonstrate the accuracy of the proposed analytical solution. The given examples reveal good agreements with those obtained by the finite element analysis. In addition, they show the advantage of the new solution as compared to the existing analytical solution which inaccurately estimates the location and magnitude of the maximum bending moment. Abubakr E. S. Musa and Husain J. Al-Gahtani Copyright © 2017 Abubakr E. S. Musa and Husain J. Al-Gahtani. All rights reserved. Postheated Model of Confined High Strength Fibrous Concrete Tue, 13 Dec 2016 13:03:37 +0000 HSC normally suffers from low stiffness and poor strain capacity after exposure to high temperature. High strength confined fibrous concrete (HSCFC) is being used in industrial structures and other high rise buildings that may be subjected to high temperature during operation or in case of an accidental fire. The proper understanding of the effect of elevated temperature on the stress-strain relationship of HSCFC is necessary for the assessment of structural safety. Further stress-strain model of HSCFC after exposure to high temperature is scarce in literature. Experimental results are used to generate the complete stress-strain curves of HSCFC after exposure to high temperature in compression. The variation in concrete mixes was achieved by varying the types of fibre, volume fraction of fibres, and temperature of exposure from ambient to 800°C. The degree of confinement was kept constant in all the specimens. A comparative assessment of different models on the high strength confined concrete was also conducted at different temperature for the accuracy of proposed model. The proposed empirical stress-strain equations are suitable for both high strength confined concrete and HSCFC after exposure to high temperature in compression. The predictions were found to be in good agreement and well fit with experimental results. Kaleem A. Zaidi, Umesh K. Sharma, N. M. Bhandari, and P. Bhargava Copyright © 2016 Kaleem A. Zaidi et al. All rights reserved. Hysteresis and Soil Site Dependent Input and Hysteretic Energy Spectra for Far-Source Ground Motions Tue, 06 Dec 2016 12:25:00 +0000 Earthquake input energy spectra for four soil site classes, four hysteresis models, and five ductility levels are developed for far-source ground motion effect. These energy spectra are normalized by a quantity called velocity index (VI). The use of VI allows for the creation of dimensionless spectra and results in smaller coefficients of variation. Hysteretic energy spectra are then developed to address the demand aspect of an energy-based seismic design of structures with 5% critical damping and ductility that ranges from 2 to 5. The proposed input and hysteretic energy spectra are then compared with response spectra generated using nonlinear time history analyses of real ground motions and are found to produce reasonably good results over a relatively large period range. Mebrahtom Gebrekirstos Mezgebo and Eric M. Lui Copyright © 2016 Mebrahtom Gebrekirstos Mezgebo and Eric M. Lui. All rights reserved. Influence of Local Sand on the Physicomechanical Comportment and Durability of High Performance Concrete Thu, 01 Dec 2016 11:18:42 +0000 This research consists of incorporating the crushed sand (CS) in the composition of a concrete and studies the effect of its gradual replacement by the sand dune (SD) on sustainability of high performance concrete (HPC) in aggressive environments. The experimental study shows that the parameters of workability of HPC are improved when the CS is partially replaced by the SD (<2/3). However, a high content of SD (>1/3) additional quantities of water is needed to meet the workability properties. The mechanical strengths decrease by adding the SD to CS, but they reach acceptable values with CS in moderate dosages. The HPC performances are significantly better than the control concrete made up with the same aggregates. The specification tests of durability show that the water absorbing coefficients by capillarity increase after adding SD to the CS. Nadia Tebbal and Zine El Abidine Rahmouni Copyright © 2016 Nadia Tebbal and Zine El Abidine Rahmouni. All rights reserved. Long Term Compression Strength of Mortars Produced Using Coarse Steel Slag as Aggregate Wed, 16 Nov 2016 08:55:43 +0000 The paper reports on some experimental results obtained from the production of mortars prepared using a commercial cement, coarse steelmaking slag, superplasticizer, and water. The behaviour of this reference composition was compared to that of some others containing further additives in order to investigate materials compressive strength after long time ageing. It has been demonstrated that an optimized water/cement ratio coupled with slag particles of size lower than 2.5 mm and proper protocol of preparation leads to the production of materials with good mechanical properties after 28, 90, and 180 days of ageing. The resulting materials therefore appeared as good candidates for civil engineering applications. However, the present research also demonstrates that the mortar samples of all of the compositions prepared suffer from decay and compressive strength decrease after long time ageing in water. In the present paper the results are explained taking account of materials residual porosity and alkali silica reaction which occurs in the samples. Erika Furlani and Stefano Maschio Copyright © 2016 Erika Furlani and Stefano Maschio. All rights reserved. Estimating Compressive Strength of High Performance Concrete with Gaussian Process Regression Model Wed, 12 Oct 2016 11:37:17 +0000 This research carries out a comparative study to investigate a machine learning solution that employs the Gaussian Process Regression (GPR) for modeling compressive strength of high-performance concrete (HPC). This machine learning approach is utilized to establish the nonlinear functional mapping between the compressive strength and HPC ingredients. To train and verify the aforementioned prediction model, a data set containing 239 HPC experimental tests, recorded from an overpass construction project in Danang City (Vietnam), has been collected for this study. Based on experimental outcomes, prediction results of the GPR model are superior to those of the Least Squares Support Vector Machine and the Artificial Neural Network. Furthermore, GPR model is strongly recommended for estimating HPC strength because this method demonstrates good learning performance and can inherently express prediction outputs coupled with prediction intervals. Nhat-Duc Hoang, Anh-Duc Pham, Quoc-Lam Nguyen, and Quang-Nhat Pham Copyright © 2016 Nhat-Duc Hoang et al. All rights reserved. Advancements in Design, Analysis, and Retrofitting of Structures Exposed to Blast Tue, 04 Oct 2016 11:48:52 +0000 Chiara Bedon, Claudio Amadio, Li Chen, Vasant Matsagar, Frank Wellershoff, and Xihong Zhang Copyright © 2016 Chiara Bedon et al. All rights reserved. Durability to Chemical Attack by Acids of Epoxy Microconcretes by Comparison to Cementitious Ones Thu, 29 Sep 2016 16:16:32 +0000 This research deals with the durability of micropolymer concrete (MPC) obtained by mixing an epoxy resin with fine and coarse sand particles. In particular the resistance of the micropolymer concrete to chemical solutions (citric acid C6H8O7, sulfuric acid H2SO4, and hydrochloric acid HCl) is investigated and compared to this of Portland cement microconcrete. Two MPC are tested. The first is formulated with 9% mass fraction of epoxy polymer whereas calcareous fillers have been incorporated in the second formulation in order to reduce the percentage of the epoxy binder. It is shown that a microconcrete designed with 7% of epoxy, 10% of fillers, and 83% of aggregates is characterized by higher physical and mechanical properties than those of the MPC formulated with 9% of epoxy binder. The mechanical properties of the resulting materials after their exposure to the three selected acid solutions at different durations were studied through compressive, three points bending and ultrasonic wave propagation tests. The obtained results are compared to those of microcement concretes (MCC) tested under the same conditions as MPC. The results show that both microepoxy polymer concretes exhibit better mechanical properties and highest resistance to chemical attack than the microcement concrete. Elhem Ghorbel and Murhaf Haidar Copyright © 2016 Elhem Ghorbel and Murhaf Haidar. All rights reserved. Blast Protection of Unreinforced Masonry Walls: A State-of-the-Art Review Wed, 21 Sep 2016 12:51:02 +0000 The recent rise of terrorist attacks has reinforced the need for mitigation of damage caused by blast loading on unreinforced masonry walls. The primary goal of the techniques is to prevent the loss of life while simultaneously preserving the integrity of the structure. This paper presents a compilation of recently available literature on blast protection of unreinforced masonry walls. It seeks to present the state of the art in this field, including mitigation techniques considered as well as testing methods selected. Fiber reinforced polymers and polyurea are the two dominant retrofitting techniques being assessed in the field. Other techniques include but are not limited to polyurethane, steel sheets, and aluminum foam. Since there is no widely implemented standard for blast loading test procedures, direct comparisons between the efficiencies of the mitigation techniques proposed are not always feasible. Although fragmentation is an indicator of the efficiency of retrofits, it is currently measured by subjective observation of postblast debris. Lucas Lantz, Joshua Maynez, Wesley Cook, and Claudia Mara Dias Wilson Copyright © 2016 Lucas Lantz et al. All rights reserved. Fracture Mechanics Models for Brittle Failure of Bottom Rails due to Uplift in Timber Frame Shear Walls Tue, 20 Sep 2016 08:00:07 +0000 In partially anchored timber frame shear walls, hold-down devices are not provided; hence the uplift forces are transferred by the fasteners of the sheathing-to-framing joints into the bottom rail and via anchor bolts from the bottom rail into the foundation. Since the force in the anchor bolts and the sheathing-to-framing joints do not act in the same vertical plane, the bottom rail is subjected to tensile stresses perpendicular to the grain and splitting of the bottom rail may occur. This paper presents simple analytical models based on fracture mechanics for the analysis of such bottom rails. An existing model is reviewed and several alternative models are derived and compared qualitatively and with experimental data. It is concluded that several of the fracture mechanics models lead to failure load predictions which seem in sufficiently good agreement with the experimental results to justify their application in practical design. Joergen L. Jensen, Giuseppe Caprolu, and Ulf Arne Girhammar Copyright © 2016 Joergen L. Jensen et al. All rights reserved. Erratum to “Modeling of Hydrophysical Properties of the Soil as Capillary-Porous Media and Improvement of Mualem-Van Genuchten Method as a Part of Foundation Arrangement Research” Wed, 14 Sep 2016 13:03:22 +0000 Vitaly Terleev, Aleksandr Nikonorov, Vladimir Badenko, Inna Guseva, Yulia Volkova, Olga Skvortsova, Sergey Pavlov, and Wilfried Mirschel Copyright © 2016 Vitaly Terleev et al. All rights reserved. Flutter Derivatives Identification and Aerodynamic Performance of an Optimized Multibox Bridge Deck Sun, 04 Sep 2016 13:24:53 +0000 The bridge deck sections used for long-span suspension bridges have evolved through the years, from the compact box deck girders geometrical configurations to twin-box and three-box bridge decks sections. The latest generation of split and multiple-box bridge decks proved to have better aerodynamic behavior; thus further optimization methods are sought for such geometrical configurations. A new type of multibox bridge deck, consisting of four aerodynamically shaped deck boxes, two side decks for the traffic lanes and two middle decks for the railway traffic, connected between them by stabilizing beams, was tested in the wind tunnel for identifying the flutter derivatives and to verify the aerodynamic performance of the proposed multibox deck. Aerodynamic static force coefficients were measured for the multibox bridge deck model, scaled 1 : 80, for Reynolds numbers up to 5.1 × 105, under angles of attack between −8° and 8°. Iterative Least Squares (ILS) method was employed for identifying the flutter derivatives of the multibox bridge deck model, based on the results obtained from the free vibration tests and based on the frequency analysis the critical flutter wind speed for the corresponding prototype of the multibox bridge was estimated at 188 m/s. Zhida Wang and Elena Dragomirescu Copyright © 2016 Zhida Wang and Elena Dragomirescu. All rights reserved. Experimental Study of the Effectiveness of Sacrificial Cladding Using Polymeric Foams as Crushable Core with a Simply Supported Steel Beam Sun, 04 Sep 2016 10:14:05 +0000 The present paper focuses on the study of the effectiveness of the sacrificial cladding using polymeric foam as crushable core to reduce the delivered blast energy using a simplified structure. The latter consists of a simply supported steel beam under a localized blast load. The tested sacrificial cladding has a cross-sectional area of 80 × 80 mm2. The effect of the front plate mass and the crushable core properties (plateau stress and thickness) is studied. Three polymeric foams are investigated: (a) the expanded polystyrene foam (PS13) with a density of 13 kg/m3, (b) the closed-cell polyurethane (PU30) with a density of 30 kg/m3, and (c) the open-cell polyurethane (PU50) with a density of 50 kg/m3. Four front plate masses are used: 144, 188, 336, and 495 g. All possible combinations are tested to determine their absorption capacity. The obtained results show that the absorption capability increases by increasing the front plate mass, the plateau stress, and the thickness of the crushable core. The open-cell polyurethane PU50 performs better. Disintegration problems are observed on the expanded polystyrene PS13 after the end of the compression process. H. Ousji, B. Belkassem, M. A. Louar, B. Reymen, L. Pyl, and J. Vantomme Copyright © 2016 H. Ousji et al. All rights reserved. Clever House Made by Using a New Kind of the Nanocomposites Thu, 01 Sep 2016 11:49:10 +0000 The materials of this paper concern a new nanocomposites perspective for construction. The development of research in the field of production and application of nanocomposite materials has made it possible to develop building materials, having high exploitation characteristics. One of such materials is a polydisperse armed water soluble epoxy composite coat, named “EpoxyPAN.” This material consists of the water soluble epoxy resin filled by the high strength inorganic fillers and the unique nanocarbon particles, astralenes and nanoporous microfiber. It was found that EpoxyPAN is possible to be used as effective water protection coating and simultaneously as effective electromagnetic waves absorber. The physical and exploitation properties of this nanocomposite and the possible ways of its applications for the Clever House constructions are also described in this paper. Andrey Ponomarev and Timur Plavnik Copyright © 2016 Andrey Ponomarev and Timur Plavnik. All rights reserved.