Practice Periodical on Structural Design and Construction

Better understanding of the connection between piles and pile caps/footings is needed so that future designs and design reviews can be adequately performed. This review paper presented discussions on the published experimental and analytical studies on prestressed concrete piles, steel H-piles, or steel pipe piles with cast-in-place (CIP) or precast footings, and/or pile cap connections with a focus on (1) pile embedment to achieve a fully fixed or pinned moment connection; (2) behavior of the pile embedment length when not treated by a special connection detail; and (3) reinforcement details to decrease the embedment length and develop fixity with a plain pile. The length of the pile embedment contributing to achieving a full fixity condition has a critical impact on substructure cost involving pile-to-pile cap (PTPC) connections. The design procedures involving piles subjected to lateral loading require a proper understanding of the fixity and ductility levels provided by the PTPC connections. Discussions on finite-element analyses (FEAs) were presented, including behavior predictions of the connections at both global and local levels. The study points to the need for modifications to the design of the PTPC connections in the existing standard codes/specifications.

Earthquake-induced uplifting/settlement at the base of liquid-storage tanks causes yielding in the bottom plate. Limited amount of yielding is a source of deformability and damping in tanks, but excessive yielding during repeated cycles can rupture the bottom plate and cause the liquid to leak from the tank. This study is conducted to experimentally determine the amount of plastic yielding that can be allowed in the bottom plate during the expected number of load cycles. Four test specimens for this study were obtained from a tank that was demolished after 66 years of service. A novel test protocol is developed for engineers to account for the large number of load cycles expected during a magnitude M 9 earthquake in the region of interest. From the results of cyclic tests, it is determined that (1) the bottom plate can sustain 20 cycles of $\pm 0.335$ rad ($\pm 19°$) plastic rotation without rupture; and (2) the plastic moment capacity of the bottom plate increases by 32% due to strain hardening. These results are significant in performance-based seismic design and evaluation of liquid-storage tanks.

The seismic performance of supplemental clutching inerter dampers (CID) for continuous span isolated bridges is assessed. The resisting force of the CID is considered nonlinear and proportional to the relative acceleration, and zero when detached. Iterative spectral analysis with the complex frequency response function under stationary earthquake excitation is used to obtain the stationary response of the isolated bridge. The iterations are required as the equivalent linear model of the CID was considered in place of nonlinear, which depends on the isolated bridge’s response. The effectiveness of the CID in controlling the response of isolated bridges is studied under important system parameter variations, namely the pier time period, isolation period, isolation damping ratio, inertance ratio of the CID, and placement factor. The CID adds damping and is quite effective in controlling the response of the isolated bridges. In addition, it was also discovered that there is an optimal value of the CID inertance for which the bridge deck’s root mean square absolute acceleration is at its lowest. The optimum inertance of the CID is influenced by the system parameters. The CID was also observed to effectively control the seismic response of the isolated bridges under real earthquake excitation. Finally, there was a good correlation of the response of the isolated bridges with the CID subjected to a real earthquake with that obtained under stochastic excitation.

The electromechanical piping systems of buildings either hang or pass through reinforced concrete (RC) beams and thus induce longitudinal and transverse holes. According to the literature, the small longitudinal hole has a minor effect on the strength and stiffness of the RC beam and thus can be ignored. However, a large hole has a significant impact on strength and stiffness and should be considered in the design. The reduction in stiffness and strength of RC beams with a large longitudinal hole can be recovered with fiber-reinforced polymer (FRP) composite material. This paper aims to study the effectiveness of different strengthening schemes with near-surface mounted carbon FRP (NSM-CFRP) for simply-supported RC beams with a longitudinal circular hole. The nonlinear finite-element (NLFE) model was proposed and then validated with 10 experimental tests from literature and in house by the authors. The NLFE model was employed to study the key parameters affecting the hollow RC beams, including the hole size, location, and strengthening with the NSM-CFRP strips scheme. The results showed that for the unstrengthen RC beams with a large hole, the optimal location was near the neutral axis with minimal reduction in strength and stiffness. For the same number of NSM-CFRP strips, the bottom strengthening scheme was less effective than the side scheme. The effectiveness of the combined (bottom and sides) strengthening schemes depended on the hole location, with the optimal hole location at the bottom compared to the middle of the beam.

Carbon fiber–reinforced polymer (CFRP) composites’ performance on metallic tubular sections under compression was investigated in this work. The strength and stiffness of CFRP strips strengthened metallic samples were estimated. Fiber plies were used in the band layout having a width of 70 mm, and the distance between the adjacent strips was kept at 60 mm. CFRP strips were externally wrapped in the steel tube with 1, 2, and 3 layers. All test samples were tested in a column testing machine. Experimental results indicated that the addition of CFRP layers exhibited more strength, ductility, and stiffness compared to the unwrapped sample. The addition of three CFRP layers showed an average compressive strength improvement of up to 35% compared to the bare sample.

Response of underground structures to buried explosion is very complex involving multiple phenomena occurring simultaneously. Studies focusing on this topic have gained momentum on account of increased terrorist threats involving explosives. However, due to multiple reasons experimental data are scarcely available. Computational modeling presents as a suitable alternative. Responses of tunnels subjected to subsurface and surface explosion are numerically investigated using LS-DYNA version R10.1.0. The interaction of blast loading with tunnels and damage mechanisms are studied considering the two burst cases. The location of explosive is further changed with respect to tunnel and its effect on damage response is studied. Three subcases designed based on location variation are side-burst, oblique side-burst, and overhead burst. Additional parametric study is performed with factors like stand-off distance and compressibility of soil. Soil compressibility is controlled by the hydrostatic compression curve, and the effect of both loading and unloading path on response of tunnel structure is investigated. A multimaterial arbitrary Lagrangian–Eulerian (MM-ALE) approach is used to model the problem, wherein soil is modeled in two parts (i.e., Lagrangian and Eulerian) to avoid numerical issues. Lastly, a solution to avoid numerical instability caused by the excessive mesh deformation at the Lagrangian–Eulerian interface of soil domain is suggested.

Several methods for predicting the one-way shear strength of reinforced concrete beams and one-way slabs are available in the literature. An assessment regarding the accuracy of a selection of one-way shear strength methods for reinforced concrete members is described in this paper. These methods include American Concrete Institute (ACI) 318 procedures in addition to several potential design methods proposed by various researchers. Predictions of these methods are compared with a set of experimental results reported in the literature. The objective is to provide engineers guidance to select the most appropriate shear design method for a given structural application. Almost all methods included in this analysis exhibit satisfactory predictions. The new ACI 318-19 shear design method is the simplest of the methods reviewed, and it gives reasonably accurate predictions for members with or without shear reinforcement.

The study presents the calibration procedure and the different challenges that arise with the selection of the material and plasticity parameters for the nonlinear finite-element analysis (FEA) of reinforced concrete structures. Two concrete models, the concrete damaged plasticity (CDP) and the concrete smeared cracking (CSC), are considered within the context of the computational model validation to provide a better understanding of their modeling parameters and to investigate their capabilities. The study describes each concrete model, and then previously tested plain and reinforced concrete specimens are analyzed under different loading conditions. The outcomes show that the CDP model predicts the response of the reinforced concrete specimens accurately, while the CSC model fails to capture the response of the analyzed specimens mainly due to convergence issues. Finally, the sensitivity of the numerical results on the fineness of the mesh is also presented, followed by suggestions to overcome this mesh sensitivity.

Reinforcement corrosion in columns may be due to a variety of reasons. Corrosion products exert high pressure in the surrounding concrete, causing the cover to spall and thus exposing the steel reinforcements. This paper described the results of an experimental test for repairing weakened columns due to the corrosion of lateral and longitudinal steel. The repair was based on removing the corroded steel (longitudinal and lateral steel) while keeping the internal concrete core fit and repairing using steel-fiber concrete (FRC) jackets and various manufacturing techniques and maintaining a cross section similar to that of the original column section. The main objective of this work was to test the efficiency of different repair jackets, seeking the original column capacity without increasing the cross section. Two monolithic columns were used as control specimens, and 20 repaired columns were tested under axial load. The main variables in this work were the volume of the fraction of steel fibers in the concrete jackets, the size of the core, shear connectors, confinement of the internal core, and confinement of the full section. The effectiveness of repair methods was measured in terms of crack pattern and column strength. The study investigated the efficiency of FRC and confinement of the internal core for repairing the corroded columns, which results in higher axial resistance than in the original column. The stud shear connector proved ineffective in enhancing the original column’s axial load–carrying capability. To account for the concrete confinement stress in the repaired column, a mathematical approach was proposed. The load-carrying capacity calculated using the proposed method agreed well with the test results.

Mass timber is emerging in new markets for wood buildings, requiring more design knowledge to compete with other structural materials. Large, in-plane tests on cross-laminated timber (CLT) diaphragms ($\mathrm{4,570}\times \mathrm{4,570}\mathrm{mm}$) were used to quantify ductility through the diaphragm force reduction factor ($R_s$) and m-factors from ASCE standards, and validate common design methods. Tests demonstrated that CLT can function well as a diaphragm with a mean $R_s$ value of 1.19, comparable with precast concrete having an $R_s$ from 0.7 to 1.4. Like precast concrete systems, CLT diaphragms depend on the interpanel connections for ductility. ASTM methods validated the assumption that a CLT diaphragm is shear-controlled for the purposes of determining $R_s$. ASCE m-factors are indirect measures of the nonlinear deformation capacity of a component and are multipliers on the expected strength. The m-factors observed (0.46 to 1.9 for immediate occupancy to collapse protection performance levels, respectively) were lower than those in previous studies on similar panel-to-panel connections. The initial stiffness of the large diaphragm panel-to-panel connections, $6.86\mathrm{kN}/\mathrm{mm}$ ($39.8\mathrm{kip}/\mathrm{in.}$), was lower than the estimate of spline stiffness of $11.5\mathrm{kN}/\mathrm{mm}$ ($65.7\mathrm{kip}/\mathrm{in.}$) from individual fastener tests. Hysteretic loading resulted in a lower spline stiffness of $4.37\mathrm{kN}/\mathrm{mm}$ ($24.9\mathrm{kip}/\mathrm{in.}$), while monotonic testing showed a mean spline stiffness of $9.04\mathrm{kN}/\mathrm{mm}$ ($52.5\mathrm{kip}/\mathrm{in.}$). CLT diaphragm displacement based on National Design Specification methods was conservative compared to test results in determining diaphragm flexibility.

The management of subsurface utilities contributes significantly to the resilience of modern cities. Damage to subsurface utilities greatly impacts daily life and has severe consequences, including property damage, scheduling delays, and fatal and nonfatal injuries. One call centers are the cornerstone for preventing subsurface utility damage in the United States. Construction contractors and subcontractors rely on one call centers to notify utility owners about their excavation plans. The shared responsibility approach, which calls for teamwork between excavators and utility owners, is a crucial element of the one call system. This study aims to benchmark one call centers’ current practices to improve the overall communication among stakeholders and enhance damage prevention efforts. The provided benchmarking suggests the dire need for better strategies to collect and analyze the data from damage events. In addition, the practical outcomes of the North Carolina Locate Resolution Partnership Committee (NC Resolution Committee) were assessed. The assessment suggests that using data from one call centers could lead to a resilient damage prevention process. Thus, this study delivers a better understanding of the current practices of one call centers and a new approach to improving damage prevention efforts beyond the traditional role of one call centers.

Calcined clays as supplementary cementitious materials (SCMs) have the potential to answer the need for SCMs because they have many resources in comparison with other SCMs. Moreover, calcined clays can be combined with limestone, which makes limestone calcined clay cement (LC3). LC3 can reduce the clinker of cement, which leads to the reduction of carbon dioxide pollution. The application of calcined clays as SCMs can make concrete with lower cost and the same compressive strength in comparison with other SCMs such as fly ash. Therefore, in this research, a predictive model has been built by the application of an artificial neural network (ANN), which can encourage the industry to increase the clay application in concrete. On the other hand, for improving the performance of the ANN model, four different optimization algorithms, such as genetic algorithm (GA), Bayesian optimization with a Gaussian process (BO-GP), Bayesian optimization with tree parzen estimator (BO-TPE), and hyperband algorithm, have been applied to optimize the number of neurons, number of hidden layers, activation function, number of batches, and epochs to predict the compressive strength of concrete. The results performance of models showed the superiority of the hyperband algorithm in running time and accuracy.

Compared to linear analysis approaches, nonlinear analysis of bridge models under large seismic demands has enabled more realistic prediction of global and local responses. However, the sensitivity to modeling assumptions, element and material formulations, software-dependent implementations, and parameter selection may lead to variable results between nonlinear analysis software packages. While previous work has led to a better understanding of how to model nonlinear static response of bridge components and systems, seismic loads and the corresponding material hysteresis introduce additional sources of variability in the nonlinear response. Two ordinary standard bridges in California were analyzed using simplified steel and concrete constitutive models in concentrated plasticity elements for the columns and nonlinear gap-link springs for the abutments. The models were implemented in SAP2000 and OpenSees and calibrated to achieve common material, section, and element-level nonlinear static responses. Subsequently, the models were extended to seismic excitation with common unloading-reloading rules for the material models as well as common definitions for damping and mass. Analysis results showed consistent drift, base shear, and moment-curvature response histories between the software packages. However, the nonlinear seismic response sensitivity for alternative column hinge formulations and abutment models should be investigated in future studies.

In this paper, a substructuring method is presented for calculating the displacement of cable domes. This method obtained matrices as a canonical form in cyclic structures using graph theory. This method helps to avoid the generation of the entire matrices. Then, a solution for the eigenproblem is presented and nonlinear equations are solved by the Newton–Raphson method. In this paper, the cable domes are prestressed rotationally repetitive structures that are cyclically symmetric, having cable part and compression strut part. For clarifying the benefits of the proposed method, both the usual method and the substructuring method are performed for some examples. Results show that the time and memory are considerably (more than 80%) saved in the substructuring approach.

This study investigated the efficiency of strengthening low-strength RC short columns with fiber-reinforced cementitious matrix (FRCM). Twelve columns were cast with concrete with a compressive strength of 18 MPa. All columns had a reinforcement ratio of 1.5%. The investigated parameters were the column cross section (square or circular), the spacing between the ties (90 and 180 mm) selected based on the columns’ dimensions, and the number of FRCM layers used in wrapping the columns [zero, two, and four layers of paraphenylene-ben-zobisoxazole (PBO) FRCM]. All columns had a clear height of 800 mm and were tested monotonically until failure. Results showed that for columns wrapped with two PBO-FRCM layers, using a tie spacing of 90 mm eliminated the effect of varying the cross section. However, circular columns showed a higher increase in capacity than square columns for a tie spacing of 180 mm, where the increase was 40%. For all columns wrapped with four PBO-FRCM layers, the cross-section shape was the sole influence on ultimate capacity, where circular columns noticeably showed a more improved capacity. Also, column load–strain relationships were only influenced by the tie spacing. All strengthened columns showed improved ductility with the increase in PBO-FRCM layers. Using existing design provisions, the theoretical capacity of the columns was calculated, and results showed that the code underestimates ultimate capacity, where the theoretical capacities were lower than the experimental ones by 5%–20%.

Plaxis is a software program widely used in Singapore for the analysis of excavation problems in the Kallang Formation and the Old Alluvium. The present study showed that the soft soil creep model was the most appropriate for excavation study of a retaining wall with a stabilizing berm in the estuarine deposit and the upper and lower marine clays of the Kallang Formation, and the hardening soil model was the most appropriate for the fill, fluvial deposits, and Old Alluvium in Singapore using Plaxis. The appropriate values of soil parameters of the estuarine deposits, fluvial deposits, Kallang Formation, and Old Alluvium for excavation study required by the hardening soil and the soft soil creep models will be summarized based on the summary of design parameters of a detailed geotechnical study and a literature review of the appropriate values reported in the literature for each soil layer. The validity of using such values for Plaxis analysis will be confirmed by a comparison of the predicted deflection of a diaphragm wall with the field measurement. The appropriate values of soil parameters of the estuarine deposits, fluvial deposits, Kallang Formation, and Old Alluvium for excavation study required by the hardening soil and the soft soil creep models will be very useful for practicing engineers.

The present design method in various codes for axially loaded piles embedded in consolidating soil is not satisfactory. It is too conservative in calculating the maximum pile force. Furthermore, the additional pile settlement due to the consolidation is neglected in ascertaining whether the requirements of allowable settlement have been met. This is because the behavior of such piles is not well understood. A new step-by-step design method based on the combination of results of extensive parametric studies of an elastoplastic load transfer model incorporating pile–soil slip reported previously is presented. In contrast to the iterative procedure required by some existing methods to determine the neutral plane location, these design charts can be used to determine the pile top settlement, neutral plane location, and maximum pile load directly. Further saving in the design of pile foundation is obtained with the concept of a compensating-pile foundation.

Contracts are a means to allocate the scope of work and associated risks to the owners and contractors involved. In case of megaprojects, because there is much at stake, identifying risk factors of megaprojects and estimating their likelihoods and consequences are vital. Likewise, analyzing how the contract risks are shared between parties and predicting the possibilities of achieving the contract goals are important practices as well. This paper, through an exploratory research, describes a risk-analysis procedure and the results of applying probabilistic risk analysis (PRA) techniques on the new Iranian upstream contract framework for a real-world gas megaproject. Such a process consists of (1) gathering and reporting all risk factors affecting construction schedule, cost, internal rate of return (IRR), and gross and net revenue; (2) eliciting and debiasing expert judgments; (3) building a mathematical model to implement Monte Carlo simulation; and (4) providing the probability distribution function (PDF) of project financial parameters. Results of this paper are of interest to practitioners involved in contractual negotiations as well as those who are responsible for developing financial framework of upstream service contracts.

With the aim of developing cast-in-place geopolymer mortar hardened under ambient temperature, this study investigated the effects of the composition ratio of fly ash (FA) and ground granulated blast furnace slag (GGBFS) and various alkaline liquids on the compressive strength and density of FA-GGBFS-based geopolymer mortar. Test results clearly show that an increase in GGBFS content in FA-GGBFS-based geopolymer mortar increases the compressive strength, and at least 20% replacement of FA with GGBFS by weight can be sufficiently used as cast-in-place geopolymer mortar under ambient temperature conditions. In this study, various alkaline liquids are characterized by the molar ratios of alkaline metal Na-to-${\mathrm{H}}_2\mathrm{O}$ and silicon-to-alkaline metal Na, which are referred to as the alkali/water ratio and silicon/alkali ratio, respectively. In each FA-GGBFS binder mixture, there is a linear relation between the compressive strength and alkali/water ratio if the silicon/alkali ratio within a the certain range.

Day by day, technology has been changing progressively because of the remarkable hastening of research and development activities. Perforated beams are one such example of advancement in construction technology. Steel beams with web openings are those that have regularly spaced web openings along the length of the beam. The web openings are created in various ways such as wire cutting and welding. Castellated and cellular beams differ in the creation of web openings. Studies addressing the effect of web post width of steel beams with web openings on the strength capacity of beams are rare. Therefore, the objective of the present work was to examine the influence of web post width on the strength capacity of beams with web openings. First, experimental tests were carried out on three full-scale specimens of a steel beam with oval-shaped web openings, cellular beam, and solid web beam. The same beam was modeled using finite-element software ANSYS and the behavior was compared in terms of load–displacement curve and failure modes. Later, a detailed parametric study was carried out to study the behavior of beams with web openings having variation in web post width using nonlinear finite-element analysis. The simply supported steel beams with web openings subjected to midspan concentrated load with varying web post width and shape of openings were modeled and analyzed. From the analysis results, it was found that the shape of web openings and the web post width play an important role in the strength capacity of the perforated beams. The maximum strength reduction capacity was found to be 51.78% for hexagonal openings of depth 150 mm and having a web post width of 50 mm. The minimum strength reduction capacity was found to be 8.93% for hexagonal openings of depth 100 mm having a web post width of 500 mm. Web post width plays a significant role in the ultimate strength capacity of beams. Web post buckling is a predominant failure mode in steel beams with web openings and it can be prevented by maintaining sufficient web post width.

The increase in the world population has led to a decrease in available resources across the globe. One such important resource is land to construct civil engineering structures. The unavailability of land resources has led to the fact that people are building structures adjacent to each other and neglecting standard guidelines for minimum separation distance between structures. This results in mutual pounding between closely spaced structures in the event of an earthquake or strong ground motions generated due to an accidental underground blast or mining activities. The present study analyzes the pounding characteristics of buildings subjected to underground blast–induced ground vibrations. Two adjacent single-degree-of-freedom (SDOF) systems are modeled as linear shear-type buildings in SAP2000, with different structural properties. The influence of friction base sliding isolations is also analyzed to prevent the pounding phenomenon. The influence of various factors—natural time period, separation gaps, charge mass, and friction coefficient—are also considered to study the pounding phenomenon. It is found that these parameters have a significant effect on structural responses and pounding characteristics.

This paper investigates the axial-compression capacity of cold-formed steel (CFS) equal angle sections with complex edge stiffeners. Both experimental and numerical analyses were carried out. In total, 10 tests were carried out and the results are presented in this paper. Preceding to compression tests, the material properties were determined and initial geometric imperfections of all the test specimens were measured. From the results of compression tests, the specimens were all susceptible to flexural buckling. A numerical model was created using the finite-element (FE) software ABAQUS version 6.11. The results of finite-element analysis (FEA) substantiated with the experimental results. The FE models were found to accurately predict the experimental behavior. Thus, the validated FE models were used for a parametric study to analyze the effect of slenderness ratio and the orientation of edge stiffeners on the axial capacity. The axial strengths obtained from parametric study were compared with the design strengths calculated by the direct strength method (DSM) from the American Iron and Steel Institute (AISI) specification. Upon comparison, it was found that the axial strengths calculated based on the current DSM are overconservative by 58% on an average.

This research work presents experimental and numerical findings of continuous rectangular spiral shear reinforcement of beam-column connections subjected to seismic type loading. A total of four exterior beam-column subassemblies with continuous, spirally bound, rectangular reinforcements and conventional stirrups as closed manner control specimens were considered. For the spirally strengthened specimens, three different stirrups angle inclines (75°, 80°, 85°) were adopted, and their performances were compared in terms of hysteresis pattern, failure behavior, skeleton curve, stiffness degradation, and energy dissipation. Specimens with stirrups inclination angles of 75°, 80°, and 85° exhibited 14%, 28%, and 19% improvements in terms of load-carrying capability over the referred specimen, respectively. In addition to that, a numerical investigation was also carried out using ATENA version 5.3.4 finite element software to validate the experimental result. The developed numerical model shows good correlation with the experimental result and can be used in the design of spiral-strengthened reinforced concrete (RC) members.

In this paper, a mathematical model is developed to predict the fly-ash brick compressive strength using three easily measurable parameters such as water absorption, initial rate of absorption, and dry density. This model will provide first-hand knowledge on the strength and quality of bricks at the construction site without the need for any large testing equipment. Additionally, an empirical model is proposed to predict the compressive strength of fly-ash brick masonry. Both proposed models are validated using the experimental results reported in the previous literature. These models can be used to standardize the quality control of fly-ash brick and its masonry at the construction site.

Externally bonded (EB) reinforcement and near surface–mounted (NSM) reinforcement were extensively studied to strengthen reinforced concrete beams in the last decades. However, few studies compare their effectiveness. This paper aims to study the effectiveness of EB and NSM strengthening techniques using carbon fiber–reinforced polymer (CFRP) strips in strengthening RC beams. In this study, three different parameters were studied, including the strengthening technique (i.e., NSM, EB), CFRP quantity, and NSM-CFRP distribution. In addition, two different bond behaviors were investigated, including perfect and cohesive models. A total of twelve beams were modeled, including six beams with perfect bond behavior and six beams with cohesive bond behavior. Each six tested beams include one control beam, two strengthened beams with EB-CFRP, and three strengthened beams with NSM-CFRP. All beams have the same cross-section dimensions, material properties, and steel reinforcement. The finite-element (FE) models were analyzed using a nonlinear FE analysis by ABAQUS software, and the results were validated with experimental works obtained from literature. In general, the developed FE models accurately predicted the ultimate strengths, strains, maximum deflections, and failure mode when compared to analytical and experimental results. For the same area of CFRP laminates, beams strengthened with the NSM system achieved higher ultimate strength but relatively lower stiffness when compared to beams strengthened with the EB system.

Recent aerodynamics studies suggest that previous wind tunnel testing may have underestimated peak wind loads on low-rise buildings. Also, climate change is demanding resilient constructions that can survive windstorms. The main objective of this study was to understand the reason for wind-induced damage to the cladding of high-rise buildings. We hypothesized that wall-bounded wind tunnels underestimate the peak loads that cause failure. We executed a unique large-scale ($1:50$) experiment in an open-jet facility to test the hypothesis. The advantages of this kind of wind testing include reduced blockage effects and the capability to produce complete velocity spectral content at high Reynolds numbers. We emphasized the influence of aspect ratio and scale effects on the magnitudes and distribution of pressures. We compared results from this study with those from a small-scale wall-bounded wind tunnel to reveal the importance of testing at high Reynolds numbers. The findings suggested that while mean wind pressures on cladding and components are comparable to wall-bounded wind tunnel results, the peak pressures are different. The open jet produced higher peak pressures, revealing that our initial hypothesis was correct. The higher peak pressures toward the upper part of the building agreed with real-world observations of wind damage to cladding. In addition, the results showed that aspect ratio influences the mean and peak pressure distribution on the sidewalls.

Geopolymer concrete is considered to be one of the best alternatives to portland cement concrete, partially or totally, not only because it decreases the ${\mathrm{CO}}_2$ emissions released during ordinary portland cement (OPC) production, but also due to its acceptable mechanical and durability properties. This study presents the experimental results of using fly ash (FA) and ground granulated blast-furnace slag (GGBFS) on fresh and hardened geopolymer concrete properties, considering the effects of several parameters such as binder type and content, alkaline binder ratio, molarity, $\mathrm{Si}/\mathrm{OH}$ ratio, cement ratio in the binder, water addition, and curing temperature. These parameters were studied over a wider range than in previous research using local by-product waste to determine the validity of the additives for massive production of geopolymer concrete. The studied properties were the slump, 7- and 28-day cube compressive strength, tensile strength, and modulus of elasticity. For all studied mixes, the increase of the binder content, sodium hydroxide concentration, and cement ratio of the binder enhanced the concrete properties, whereas the increase of the alkaline binder ratio, $\mathrm{Si}/\mathrm{OH}$ ratio in the solution, and additional water decreased the concrete properties. An increase of curing temperature from 30°C to 90°C improved the fly ash–based geopolymer concrete mechanical properties by an average of 35%; in contrast, the same increase in temperature decreased the concrete mechanical properties of GGBFS-based geopolymer concrete by an average of 22%. Equations for tensile strength and modulus of elasticity in terms of compressive strength were proposed and were compared with equations from standards and equations previously proposed in the literature. Finally, the environmental impact in terms of ${\mathrm{CO}}_2$ emissions was found to be on average 90% less than that of conventional concrete of the same grade.

Insufficient strength and stiffness of the kentledge system in the static pile load test will lead to test failures and even accidents. However, the codes and standards do not offer definite guidelines in this regard. This article carried out static load tests on the piles of a road bridge in Bhubaneswar, India, to highlight the importance of the kentledge strength and stiffness for the successful conduct of such tests. Based on the results of this study, the article proposed a methodology for the structural design of the kentledge system, which can be adopted to standardize the procedures of static pile load tests available in the existing codes. The findings of this study will be useful to practitioners working in pile construction.

Steel through-truss is a very common configuration for railroad and highway bridges. There is a large number of such spans in surface transportation infrastructure worldwide, especially in railway systems. In design and evaluation, these spans’ in- and out-of-plane bending have been either omitted or approximated. A fuller understanding of this effect will be able to assist in reliably designing and assessing these structures for longevity and/or increasing allowable service load to facilitate economic developments. A full scale load test is performed in this paper on five such bridges of the Canadian National Railway (CN) using train load. The main truss elements prone to in- and out-of-plane bending are identified and strain-gauged including the hanger (L1U1 or L’1U’1). Out-of-plane bending is seen to produce more significant flexural stress than in-plane bending. Three-dimensional (3D) numerical simulation is also verified by physical tests and covers other uninstrumented members of the tested spans. These results are used to evaluate the accuracy of a new and simplifying two-dimensional (2D) analysis method for the most significantly bent vertical hanger out-of-plane. The 2D method is shown to capture a significant portion of the bending but still underestimate flexural stress. An empirical and hybrid approach is therefore developed and recommended to address the inadequately accounted out-of-plane bending for routine practice of design and evaluation. It is needed when resources for detailed 3D analysis are not readily available, and/or when a quick and reliable method is needed, e.g., for verification or calibration of another method. These results are also useful for stress range estimation for fatigue analysis, although fatigue is not a concern to these bridges and is therefore not specifically addressed in this paper. CN has adopted the recommended method and the other research findings in load-rating their existing through-truss bridges.

In low seismic regions where wind loading governs structural design, the use of high-strength cold-reduced sheet steels for tension strap braces is attractive, but is hindered by a lack of material ductility that causes these braces to fracture without yielding. The present work investigates the potential solutions through laboratory tests at the brace component and at the whole shear panel levels. The slot-perforated braces with square or rounded slot ends tend to fracture at or near a slot end, while those with pointed slot ends avoid fracture there. Finite element analyses were used to confirm the experimental findings. The rounded slot end is recommended from the fabrication and deformation capacity points of view. The shear panel test results show that a normal high-strength strap brace would fracture at a screwed end without yielding, while the recommended solution can ensure substantial yielding provided the ratio of net slotted section to gross section is lower than the connection efficiency defined in the present work. The shear panel’s deformation capacity can be controlled via the slot length. The desired slot length can be split into multiple slot perforations along the brace to facilitate inline punching during fabrication.

Formwork is an essential part of construction engineering, whether for floors or for walls. This research focused on wall formwork, which is used in residential buildings. This study primarily was concerned with reducing the cost of the formwork using optimal sections and optimum casting rates. The methodology of this research consisted of using equations to determine the lateral pressure of concrete on the formwork, to calculate the minimum spacing between the formwork components to obtain an economical and safe design, to calculate the optimum casting rate, which is $1.5\mathrm{m}/\mathrm{h}$, and to find the optimum lateral pressure.