Practice Periodical on Structural Design and Construction

Planning work conducted early during a construction project, known as front end planning (FEP), has a large impact on project outcomes and significant influence on the configuration of the final project. As a key component of FEP, front end engineering design (FEED) plays an essential role in the overall success of large industrial projects. This work was motivated by the existing confusion about the quality and completeness of the desired engineering deliverables at the end of FEED. The objective of this research was to determine the perception of the FEED process by administering a thorough survey to experienced FEED professionals working on industrial projects. A key finding of the survey is that the industry lacks a consistent, agreed-upon FEED definition, which causes industry misunderstandings. To address this gap, a comprehensive FEED definition was developed based on the 80 survey responses received, and builds on the existing literature. The contributions of this work include: (1) developing a tested FEED definition for the large industrial projects sector; (2) determining the industry’s state of practice for measuring FEED deliverables; and (3) reaffirming that 30% of engineering design complete is a threshold for FEED. These contributions to the FEED body of knowledge will add consistency and clarity regarding FEED for large industrial projects, promoting the alignment of academics and project stakeholders on a common understanding of FEED and improving communication about FEED expectations. In addition, this work is intended to serve as a foundation and definition for future FEED research.

Experimental and analytical study of an innovative strengthening system for deep corrugated structural plates ($381\text{-}\mathrm{mm}$ pitch by $140\text{-}\mathrm{mm}$ depth) is described. A typical $7.94\text{-}\mathrm{mm}$ thick deep corrugated structural plate can normally span up to 19.8 m for typical bridge design loads. In order to achieve longer spans, it is necessary to increase the flexural stiffness of the plate. The new strengthening system consists of wide flange beams connected to the corrugated structural plate using rigid brackets. Several tests were conducted at the University of Cincinnati Large Scale Testing Facility to evaluate the behavior and stiffness of the beam-plate system. Tests were carried out using a number of different reinforcing beam sizes and bracket spacings. Equations for determining the cross-sectional properties and capacity of the stiffened system were developed. Design case studies were conducted using a special finite element program called CANDE (Culvert ANalysis and DEsign). Different plate gauges in combination with a number of wide flange beams were used in the finite element analyses. The efficiency of the strengthened system was evaluated. In this paper, recommendations are made for design and analysis of strengthened long-span buried bridges, i.e., culverts. This study has found that it is possible to design lighter, longer, and more cost-effective structures through the use of stiffened plates.

Shortening delays for immediate access to essential public infrastructures when subjected to rare extreme loadings are critical to promptly normalize socioeconomic activities. Public infrastructure networks contain numbers of bridges prone to accidental vehicular impact loading. This paper investigates the response of as-built and carbon fiber reinforced polymers (CFRP)-strengthened bridge piers struck with lightweight and medium-weight vehicles at a city speed limit of $56\mathrm{km}/\mathrm{h}$, a highway speed limit of $100\mathrm{km}/\mathrm{h}$, and a police chase speed of $150\mathrm{km}/\mathrm{h}$. The present study involves the development of three-dimensional (3D) complex nonlinear finite element analysis models of a 13.4 m 3-lane-wide and 7.9 m high AASHTO-LRDF-designed single hammerhead bridge pier. Two publicly available vehicle finite element models representing lightweight and medium-weight trucks were used in the study. An explicit 3D nonlinear finite element software program LS-DYNA was used to simulate vehicle pier collisions. The complete vehicle and single hammerhead bridge pier finite element model had a total of 140,577 elements and finite element analysis was performed at the Ohio Supercomputer Center. Full-scale experimental head-on collision data reported in literature and principles of energy conservation were used to validate the accuracy of the proposed finite element analysis models. Finite element analysis results revealed that CFRP composites contained impact-induced localized damages and peak dynamic impact force surpassed AASHTO design impact force.

In this paper, an analytical model to determine the flexural response of simply supported RC beams under four-point bending tests failing in flexure and shear is presented. The model is able to provide load-deflection curves, including also the shear contributions, which are determined assuming a kinematic rigid plastic model able to consider different strength contributions such as the concrete, the dowel action, and transverse reinforcement with progressive yielding. For each contribution, a physical explanation is provided to link the strength evaluation with a specific kinematic evolution for the determination of the overall response of RC beams under combined shear and flexural loads. An extensive comparison with the experimental data available in the literature is made to check the reliability of the simplified proposed model to predict also the complete flexural response of beams including postpeak resistance when shear failure is attained. The comparisons revealed good agreement between the experimental and analytical results. The proposed model can be simply used for manual calculations of the flexural response of RC beams that fail in flexure or shear.

Preserving the structural integrity of historical bridges made of wrought iron is a mandatory technical requirement in several countries in Europe. A reliable fatigue lifetime estimation of theses bridges allows for proposal of adequate maintenance policies to keep these historical structures as part of the historical legacy for the next generations. In this paper, fatigue data of German bridges built between 1850 and 1900 are considered. The Weibull model of Castilllo and the model of Stüssi to depict the Wöhler curves and estimate the fatigue limit are applied. Their results are compared with those from the linear model of Basquin, which is used in international standards.

Cylindrical concrete water tanks resting on the ground are widely used in water and wastewater treatment plants. The hoop force in the cylindrical wall is a critical design force. Rotation of the wall-bottom joint directly influences the design forces, i.e., hoop force and bending moment of the tank wall. The prevalent method of design suggests the assumption of hinge and fixed conditions at the wall bottom for the maximum value of hoop force and bending moment, respectively. However, many recent studies have shown that there is a possibility of the wall-bottom joint rotation being more than the hinged wall-bottom joint rotation. This happens in case of tanks resting on deformable strata. This paper presents a simplified analytical expression for rotation at a hinged wall-bottom joint and further develops analytical expressions for design forces for a known wall-bottom joint rotation for any tank with finite dimensions. The analytical expressions developed are ratified by finite-element analysis (FEA) as well as with standard design tables. By knowing the exact value of rotation at the wall-bottom joint and corresponding design forces, practicing engineers can assess the possible adverse effect of the deformable strata.

This paper presents a precast continuous beam-column joint that bases its structural work on the wedge effect given by the friction between the beam, concrete wedge, and column. It was used in an industrialized social building system with excellent performance and is intended to extend its use to architectural programs for residential buildings, which requires the study of the behavior of the beam-column joint. Computational modeling based on FEM implemented in the software Abaqus, calibrated against full-scale test results, is used. The numerical results showed correspondence with the experimental full-scale test. Using a statistical design of experiment approach, the influence of the axial load and the specified compression strength of the wedge concrete in the bearing load and the friction load were determined, and the percentage of loads that are transmitted by friction and by direct bearing in each area of the joint are reported. Additionally, there is statistical evidence that column axial load contributes to the development of the wedge effect, and the effect of friction on the structural performance of the joint is demonstrated.

Continuous and semicontinuous castellated composite beams can present a global buckling mode in the hogging-moment regions known as lateral-distortional buckling. In this mode, the lower portion of a steel section is compressed and the bottom flange undergoes lateral displacement and torsion as the web distorts. A common standard contains no equations for the calculation of the elastic critical moment of regular I beams, while another standard indicates a procedure for the assessment of this moment, which is used to calculate the resistant moment of these beams, based on the inverted U frame mechanism. This phenomenon also occurs in steel-concrete composite castellated beams, but there is no design procedure in current standards. In this paper, a new design procedure is presented for the purpose of determining the critical moment of castellated composite beams under a uniform hogging moment. Finite-element simulations in ANSYS commercial code were performed and compared to the proposed procedure. Results indicate the this procedure is adequate for achieving the elastic critical moment and satisfactorily considers the variation of a slab’s stiffness and the displacement of the neutral axis position in steel sections. The presented procedure led to excellent agreement with numerical results, with an average deviation lower than 3.5%.

Construction risk management processes necessarily rely on subjective assessments and heuristic rules. Historic data are desirable, but rarely are available due to the unique nature of individual construction project and the required risk assessments. A comprehensive literature review highlighted the lack of attention by researchers and industry professionals to understanding the influence of cognitive biases on construction risk management processes. The authors reviewed a representative list of 18 relevant cognitive biases from the literature that could influence risk-based perceptions, assessments, and decisions among industry practitioners. This paper discussed the application of empirically validated debiasing strategies and experimental controls for professional and academic settings. The authors also discussed the limitations associated with debiasing strategies to promote a deeper understanding of results and accurate reporting of research validity for future researchers. This work is at the nexus of risk management and behavioral psychology. It provides detailed discussion and impetus for future research to improve the rigor of the risk management process.

The present study proposes an alternative reinforcement material system, known as buckling restrained reinforcement (BRR), to improve the behavior of concrete columns loaded with earthquake-type loading in moderate seismic areas. BRR is made from circular steel tubes and placed in the main bars in the plastic-hinge-critical portion. Experimental investigations were carried out on half-scale models of concrete columns provided with and without BRR and loaded with a combination of axial loading and quasi-static reverse cyclic lateral loading. Performance improvement is observed in load–deformation characteristics, energy dissipation, and lower stiffness degradation for column specimens with the proposed BRR in comparison with specimens having light ductile detailing. Moreover, congestion of tie bars near the joint was also removed by providing BRR at the plastic hinge zone with wider tie spacing ($>33\%$) than ductile detailing, thus reducing the confining reinforcement bars by 25% and reducing the construction challenges in the field.

This paper presents the structural behavior of transmission line cables under nondeterministic dynamic wind loads (atmospheric turbulence), considering aerodynamic damping and geometric nonlinearity. A numerical methodology was developed using commercially available finite-element analysis software and applied to 32 case studies considering different spans and wind velocities. The maximum responses obtained in the dynamic simulations were compared with the results from (1) quasi-static analyses considering the mean velocity, and (2) quasi-static analyses performed according to the procedures established in a range of current standards and codes. The first comparison highlighted the importance of considering the dynamic response in cables subjected to wind loads. Among the Brazilian codes evaluated, one code showed results considerably lower than those obtained through dynamic analyses, with maximum differences of 28%. In contrast, another code showed maximum differences of approximately 10% and, in the absence of Brazilian recommendations for transmission lines projects, it can be used as a reference. A third code showed good agreement with the numerical results, indicating it to be the most appropriate code for the determination of wind forces in transmission lines cables.

Posttensioned transfer girders offer elegant solutions to support vertical members that do not extend below lower levels of high-rise buildings. The design of a posttensioned transfer girder involves selection of a preliminary section, and then optimization of girder size and the prestressing force to satisfy serviceability and ultimate design requirements. In practice, typical span-to-depth ratios are used for preliminary sizing of structures. However, in the case of transfer girders, it is not easy to set a rule-of-thumb because the depth of the member depends on the transferred load and many other parameters. Herein, a simple approach is suggested to practicing engineers for determining the depth of simply supported transfer girders with minimal trial and error. It is shown that the proposed expression gives reasonable preliminary dimensions to achieve an acceptable design in terms of serviceability.

Fencing posts are subjected to impact forces from animals like wild boars, wild cattle, and others that try to pass through them. Hence, improving the impact resistance of fencing posts is an issue of priority. Rubcrete is concrete in which crumb rubber replaces a particular volume of mineral aggregates. The impact resistance of concrete has been increased with the use of crumb rubber. Steel fibers and polypropylene fibers help in controlling macro and microcracks in concrete. Impact tests were carried out on concrete prisms with the inclusion of steel fibers at 0.25%, 0.5%, 0.75%, and 1% by total volume of concrete, and the results indicated that steel fiber content of 0.75% has the maximum strength-to-cost ratio among the steel fiber mixes. In the case of polypropylene fiber–reinforced concrete, 0.1%, 0.2%, and 0.3% polypropylene fibers were added to concrete, and it was found that the mix with polypropylene content of 0.2% had the best strength-to-cost ratio. The ratio of optimum energy absorbed to cost was observed for a rubcrete mix with 15% crumb rubber content. Static and impact tests were carried out on ordinary concrete, rubcrete, steel fiber–reinforced concrete, polypropylene fiber–reinforced concrete, steel fiber–reinforced rubcrete, and polypropylene fiber–reinforced rubcrete fencing posts, and it was observed that the steel fiber–reinforced rubcrete fencing posts performed better than the other types of posts studied.

This paper describes an experimental investigation aimed at retrofitting hot-rolled steel (HRS) channels using cold-formed steel (CFS) sections. Six simply supported specimens were tested under four-point monotonic loading. The main goal of this study was to improve lateral torsional buckling resistance by converting open HRS sections into closed sections (box type) by conveniently connecting CFS sections near the flange tips of the HRS channels. To determine the flexural benchmark parameters, one specimen was tested without being retrofitted. Four of the other specimens were retrofitted by inserting a CFS channel into the HRS section to form a box section and intermittently welding them at the flange tips along the span. The pitch of the welding varied in these four specimens. In the last specimen, a corrugated CFS plate was intermittently welded to the HRS section toward the flange tips to form a box section. The flexural performance of all specimens was evaluated in terms of ultimate strength, load-displacement response, stiffness behavior, lateral displacement, and mode of failure. The theoretical strength of the HRS channel was determined and compared with the test strengths. This study confirmed the substantial potential of CFS sections in retrofitting HRS channels under flexural loading.

In 2018, under service conditions, excessive deflections were observed in the long-span timber beams of the first floor of the former Saint Elisabeth Monastery in Palermo (Italy). The building was constructed in the sixteenth century. During the years, it underwent several modifications, and finally in 1900 it became a barrack. In the middle of the twentieth century, it was submitted to maintenance works consisting in rehabilitation of the first floor with timber beams and rehabilitation of the roof with timber trusses. An experimental investigation was carried out to establish the causes of the excessive deflection and to identify a retrofitting design. In this work, details of retrofitting design and strength verification including in situ loading tests are described and discussed. The lesson learned from the case study could help professional engineers to be aware of the main peculiarities and defects of structural systems affected by construction mistakes, and the importance of in situ periodical checks during the useful life of structures. Finally, practical indications for a possible retrofitting technique of this kind of timber structure of historical interest are given, proving to be a simple, rapid, cheap, reversible and effective retrofitting system.

As a remedy to excessive amounts of energy consumption, adverse impacts on the environment, and ineffective use of resources in the construction industry, the number of green buildings (GBs) is increasing all over the world. Design and construction of GBs involve processes different from those used for conventional buildings. Having particular activities, functions, and physical aspects, GBs impose their own difficulties during these phases. Building information modeling (BIM) systems use several software packages for virtual simulation of project characteristics, which promotes early detection of potential problems even before production of the intended design details. In this study, evaluation of Yildiz Technical University (YTU), Faculty of Civil Engineering (YTUFCE) building using BIM tools based on leadership in energy and environmental design (LEED) v4 BD+C: Schools certification system is presented, which was prepared as part of a capstone project by senior civil engineering students. First, the building was assessed with respect to achievable credits with its current state through a three-dimensional (3D) model. Students were encouraged to consider which sustainable practices would be applicable if the building was originally designed and built as a GB. Then, the building was reassessed with the intention for additional applicable credits and corresponding points. The construction phase was also reviewed for extra credit points that could be earned from construction activities to contribute to LEED certification. The main objective is to introduce students to two major trends in the construction industry, namely GB and BIM applications, and create awareness of sustainable construction, GB certification systems, and emerging technologies.

Compressed earth blocks (CEBs) have been increasingly studied and used in the past few decades as an eco-friendly alternative to regularly practiced concrete-and-masonry systems; especially in remote rural areas in developing countries. In most of the cases in which CEBs were used, mortars containing portland cement and/or other artificial binding materials have been used, which reduces the eco-friendliness of the constructed CEB structures. In the research presented in this paper, CEBs are manufactured manually using a simplified novel technique and earth-based mortars are developed using an earth mixture involving an industrial byproduct. The bond between the earth-based mortar and the CEBs was tested experimentally. The developed mortar is used to construct CEB prisms and walls after preroughening of the CEB surface. The prisms and walls were tested structurally until failure. Furthermore, the durability of the walls was assessed by performing cycles of wetting and drying on the walls. The results were found to be promising in constructing structurally sound and durable CEB buildings.

In this paper, a method is proposed for rating and quantifying a bridge’s structural resilience. The proposed method specifically focuses on the relationship between a bridge’s resilience and its structural inputs. To demonstrate the application of the proposed approach, four distinct bridges are chosen for a comparative case study. Each bridge falls into a category with varying combinations of high and low sufficiency and resilience ratings. Resilience ratings are calculated for each bridge and compared with their sufficiency ratings to demonstrate that high sufficiency is not indicative of high resilience. This paper provides an objective, yet adaptable, framework that owners can use to organize their resilience measurements. While not completely unbiased, this approach allows for a less biased assessment of the relative resilience of assets, and further justifies funding allocations or requests. The resiliency rating framework calibrates a bridge’s resilience specifically to its structural configuration. Application of the framework is demonstrated for four different bridges, and is outlined so future users can easily adopt, adapt, and calibrate to meet their specific needs.

The degradation state of RC bridge structures is one of the most important and difficult aspects to be interpreted. For these structures, structural analysis using FEM requires a reliable definition of the main mechanical properties of the materials constituting them and, in particular, a description of the actual damage state, which is a product of the damage they have suffered over the years. A general representation of material properties, including damage effects, can be performed by investigating the “global modulus (E)” of a structure. This can be determined by experimental determination of fundamental frequencies with an experimental analysis and the use of Rayleigh expressions. In this paper, referring to a practical case of a reinforced concrete Gerber beam with an advanced state of degradation, a static checkup was made using dynamic characterization. The state of the structure and its degradation due to corrosion and carbonation effects was analyzed using nondestructive and partially destructive tests. Moreover, dynamic tests were also performed to determine the fundamental frequencies (environmental trembling) to be used, through the Rayleigh method, to determine the global modulus of the structures, necessary for structural analysis. Then, a retrofitting design was designed and applied with partial reconstruction of the concrete deck by using high-performance concrete and by externally wrapping the main and secondary RC beams with carbon fiber-reinforced plastic (FRP) strips and wraps. Finally, a dynamic test was carried out to verify the efficiency of the retrofitting system adopted.

Applying advanced technologies and efficient project management techniques helped United States (US) contractors build a strong track record in international construction. Engineering News-Record (ENR) data from the early 1980s to 2008 show that US contractors led the international construction arena during that period. However, starting in 2009, Chinese construction firms took a lead in the international construction market, with increasing volume and revenue. In addition, companies from newly industrialized countries (NICs), mainly South Korea and Turkey, also increased their volumes and revenues. This study analyzes the changing trends in international construction from the beginning of the 21st century. The study also analyzes the factors that helped contractors from NICs to advance in international construction. Study findings indicate that having advanced technological capabilities and project management skills does not provide the same distinctive competitive advantage to US contractors in the 21st century’s international construction industry. US contractors need to form strategic alliances with other international companies that are successfully operating in the Middle East and Asia. Financial support from government can significantly improve US companies’ competitiveness. To improve the capabilities in delivering full-cycle services, US construction companies can acquire facilities management companies. In addition, use of emerging delivery methods and contract strategies, such as build-operate-transfer (BOT), design-build-finance-maintain-operate (DBFMO), and public–private partnerships (PPP), can improve the competitiveness of US contractors in international markets. Other strategies for US construction companies include seeking international mergers and acquisitions (M&As) to improve their performance.