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The article discusses the importance of reproducibility in academic research, particularly in the field of structural engineering. It acknowledges the challenges in achieving reproducibility, such as data storage and computing requirements, as well as proprietary issues. The authors argue for the development of a reproducibility policy in the Journal of Structural Engineering and the Journal of Bridge Engineering, taking into account the nature and culture of research in these subdisciplines. They propose a classification system that emphasizes the availability of data and metadata, and encourage authors to go beyond data availability by making models and other materials accessible. To incentivize research and data availability, the journals will provide a visible recognition badge for papers with open data/models/codes and may consider special recognition for these papers. The authors also outline the review process for data-verified papers, which involves three associate editors verifying the availability and representativeness of the data. [Extracted from the article]

This article discusses the importance of reproducibility in academic research, specifically in the field of bridge engineering. The authors argue that reproducibility is challenging due to factors such as paper documentation, technology constraints, and proprietary issues. They propose implementing a policy that encourages researchers to make their data and models available to others, although they acknowledge that full reproducibility may not always be practical. To incentivize this practice, the Journal of Bridge Engineering plans to introduce a visible recognition badge for papers that provide open data, models, and codes. The authors also outline the review process for papers seeking the "Data Verified Paper" designation. [Extracted from the article]

She holds a B.Eng. in building engineering from Tongji University (2001), a M.S. in civil engineering from the University of Massachusetts (2005), and a Ph.D. in geotechnical engineering from the Georgia Institute of Technology (2010). Dr. Tan's areas of specialization include deep excavation and tunnelling, foundation engineering, forensic geotechnical engineering, and engineering failures associated with climate change. He received his B.Eng. in building engineering from Tongji University (1999), M.Eng. in Geotechnical Engineering from Tongji University (2002), and Ph.D. in civil engineering from the University of Massachusetts (2005). [Extracted from the article]

Calculating impact forces in asymmetrical lateral structures has been a complex challenge that spans decades in engineering. Traditional models often fall short due to the inherent complexity of asymmetrical members and the need for significant computational resources or a vast pool of training data. This paper develops an approximate formula for accurately calculating the impact force of asymmetrical lateral-impact members under lateral impact. Existing methods for assessing impact forces have been limited in their application due to the inherent complexity of asymmetrical members and the significant computational resources or extensive training data they often require. Our approach employs the residuals margin method, and Laplace transforms to derive an efficient and accurate formula for impact force calculation. The paper rigorously validates this Formula through experimental testing, demonstrating high precision with an error margin of less than 5%. Further validation against diverse impact data from multiple studies on different materials and loadings under static and dynamic conditions confirmed the Formula's consistency. Despite simplifying assumptions, this research contributes a novel and computationally efficient approach for calculating impact forces. The formula offers engineers a practical tool while advancing a fundamental understanding of asymmetric impact dynamics. Rigid experimentation verified its significant accuracy, establishing the formula as a valuable structural impact analysis and design resource. This research presents an analytical formula for calculating impact forces on structures like buildings, bridges, and vehicles experiencing asymmetrical lateral impacts. Such impacts commonly occur due to falling debris, vehicle collisions, seismic pounding, and derailed train strikes. However, existing design formulas often oversimplify impact mechanics or require complex simulations. The proposed method provides engineers with a simple spreadsheet-compatible equation relating impact force directly to tangible mechanical quantities like momentum. This enables rapid impact load assessments essential for performance-based design against accidental hazards. The formula was validated through laboratory impact tests on reinforced concrete slabs, demonstrating precision within 5% of measured forces. Additional validations against published experimental and simulation data on different construction materials confirmed accuracy. The proposed formula equips structural engineers and safety analysts with a practical impact analysis tool by offering a computationally efficient approach with proven reliability. It facilitates assessing design performance for asymmetrical impact load scenarios, helping improve resilience for critical facilities subjected to hazardous lateral impacts. [ABSTRACT FROM AUTHOR]

Segmental tunnel linings have a complex structural behavior that is difficult to predict. Full-scale in situ structural monitoring allows us to gain access to these structures, observe the acting mechanisms, and better understand the actual structural behavior under realistic boundary conditions. In a recent structural monitoring project in Frankfurt, Germany, strains, deformations, and temperatures were measured at the segmental lining of a twin-tube tunnel boring machine (TBM) tunnel. Hereby, internal forces were back-calculated from the strain measurements. The results of the monitoring are presented and discussed in this paper. The measurements began immediately after the assembly of the segments and have been performed continuously over several years. Because of that, it was possible to observe that the internal forces differ significantly between the construction stage and the final state. During the construction stage, the internal forces develop quickly within hours after ring assembly, showing a distribution along the lining's circumference that is hard to predict. Almost all radial deformations occur during this period and remain unchanged afterward. After this first early phase, a period of stress redistribution follows, including significant changes in the internal forces. At its end, the stable, final state is reached. In this state, the internal forces match better with expectations. In the monitored areas, the stresses during the construction stage slightly exceeded those of the final state, which should be avoided for economic reasons. Additional investigations regard the temperature development within the lining, the influence of the second tube construction on the already built tube, and the development of longitudinal ring interaction over time. The latter significantly influences the structural behavior, but its development is often subject to uncertainties. In this case, it was observed that the longitudinal interaction decreases considerably over time. Practical Applications: In the structural design of segmental tunnel linings, structural or geotechnical engineers have various options regarding the available calculation methods and modeling strategies. All of these options are part of the state of the art, and the selection is up to the engineer. However, the results can be quite different depending on the chosen option. Consequently, uncertainties remain regarding the real linings' internal forces and structural reliability. The actual mechanisms can be identified by investigating the real structural behavior of segmental tunnel linings with in situ structural monitoring. Then, with back-analyses, on the one hand, it can be tested to determine how well different calculation methods and modeling strategies correspond to reality. On the other hand, the monitoring data can contribute to improving existing calculation methods, developing new modeling approaches, and establishing more detailed recommendations or optimizations regarding the design and construction of segmental tunnel linings. This paper presents findings derived from a structural monitoring project on a segmental lining. Different mechanisms and aspects, sometimes uncertain or debatable in tunnel design, are discussed regarding their real in situ appearance. The gained data will also be used for further back-analyses and investigations. [ABSTRACT FROM AUTHOR]

Tornadoes are intense localized convective windstorms that are among the most devastating natural hazards that occur in the United States. Although the probability of any tornado striking one particular building in any given year is quite low because of its small footprint, when strong tornadoes strike densely populated areas, the results can be catastrophic; the Joplin, MO tornado of 2011 caused 161 fatalities and nearly $3 billion in damages. Such losses are projected to increase in the future as a result of urbanization and economic development. ASCE Standard 7-22 on Minimum Design Loads has, for the first time, included new reliability-based design criteria for tornado loads. The objective of this paper is to provide archival documentation of the basis for these tornado-resistant load provisions in Chapter 32 of ASCE 7-22. This paper summarizes the significant challenges that were overcome in addressing the fundamental differences between effects of tornado and nontornadic winds and the higher uncertainties associated with tornado wind pressures that must be accommodated in the risk-informed framework of ASCE 7-22. These challenges were addressed through reliability analyses that led to new tornado load criteria that provide reasonable consistency with the reliability delivered by existing criteria for nontornadic winds. [ABSTRACT FROM AUTHOR]

Reports that the American Society of Civil Engineers (ASCE) and the Structural Engineering Institute (SEI) are looking for nominations for the 2006 ASCE and SEI Awards. Objective of the ASCE and SEI Honors and Awards Programs; ASCE awards based on meritorious papers; SEI awards.

The current construction industry for civil and structural engineering is considered to be one of the growing industries in the world. With the push toward a more digitized industry, emerging trends such as additive manufacturing and the use of three-dimensional (3D) printing technology, along with consumer demand, are resulting in automated development with multiple benefits. Successful applications for small-scale construction projects that have implemented 3D printing have shown improvements in cost, production time, and design freedom and complexity. However, for large-scale applications, there are various limitations and factors hindering the adoption of additive manufacturing technologies. In this paper, a systematic literature survey of recent 3D printing technologies was conducted specific to the area of construction engineering, and the various techniques, materials, software, and technical and nontechnical aspects were analyzed. The key applications and their benefits are outlined, and their potential for large-scale applications is articulated. Future research areas for these components are suggested to strengthen the technical readiness and feasibility of adopting 3D printing technology in construction engineering and industries. [ABSTRACT FROM AUTHOR]

The field of (practical) data-driven approaches that utilize the vibration signature of target systems for developing mathematical models (for computational purposes, control, or anomaly detection for structural health monitoring) is still an active research area, despite the fact that several powerful system identification techniques have been developed in the system dynamics field to analyze such measurements. However, there is still a paucity of comprehensive experimental studies that investigate the range of validity of such identification techniques, particularly those applicable to realistic situations encountered in the structural engineering field, with the focus on detecting, quantifying, locating, and classifying observed changes, especially when there are significant inherent nonlinearities in the reference (undamaged) complex target structure, and where there are unavoidable sources of errors and uncertainties in the measurements and the attendant data analysis procedures. The research team constructed a well-instrumented, reconfigurable test apparatus (resembling a tall building) that allows the introduction of quantifiable levels of composite changes at various locations, orientations, and types of linear and/or nonlinear changes, with the aim of investigating a subset of the aforementioned challenges facing researchers who are interested in assessing the utility of some practical system identification approaches. The primary focus of the identification approach is on a decomposition procedure that is ideally suited for certain types of structures that possess some topological features that can be exploited to enhance the detectability of small changes. A companion paper provides a detailed description of the testbed features and its instrumentation. The present paper focuses on the analysis of some of the very extensive data sets that were created to study the usefulness of some practical dimensionless probabilistic measures that not only provide normalized change indices but also simultaneously attach a confidence level to each of these indices. [ABSTRACT FROM AUTHOR]

An introduction to the journal is presented in which the editor discusses various reports within the issue on topics including the seismic fragility of steel bridges, the flutter derivatives of bridge decks and the resistance of steel orthotropic bridge decks.

Lunar bases for long-term human habitation are a topic of growing interest to engineers. Structures to be built on the surface of the Moon must be designed to resist extreme environmental hazards such as hard vacuum/no atmosphere, low gravity, ionizing radiation, large temperature variations, moonquakes, and meteoroid impacts. Protective regolith covers may provide adequate shielding from some of these hazards. This paper presents a methodology that utilizes established physics-based models to determine the immediate effects of hypervelocity impacts (HVI), including crater geometry and shock pressure, for engineering design of lunar structures. First, empirical equations and nondimensional scaling laws for computing geometric features of HVI craters are discussed. These damage estimation tools are adopted from the fields of spacecraft design and planetary impact cratering. Next, the planar impact approximation model is discussed, which utilizes one-dimensional shock wave physics and impedance matching conditions to estimate the peak initial pressures generated in HVI. Comprehensive parametric analyses, encompassing a wide range of impact velocities and impactor masses as well as a variety of impactor and target materials, are performed to demonstrate applications of the models to both regolith-shielded and unshielded structures. Crater geometry descriptors and peak shock pressures in HVI scenarios involving various impactor-target combinations are computed with in-house programs and compared with computational results reported in the literature. The analyses indicate that for a given target, the main factors determining cratering damage are impactor mass, impactor density, and impact velocity, while the initial shock pressure is influenced mainly by impact velocity and impactor density. A comparison of impact pressures experienced by monolithic unshielded targets and granular dry sand layers highlights the potential importance of providing regolith-like shielding to attenuate HVI effects. Practical implications of the study are discussed from an engineering design perspective, underscoring the considerable value of such models to practitioners. Practical Applications: A practical methodology for determining cratering and peak shock pressure due to hypervelocity meteoroid impacts on unshielded and regolith-shielded lunar structures is proposed in this work. The methodology utilizes well-established physics-based models of hypervelocity impact effects. These models have several advantages that make them suitable for inclusion in lunar structural design guidelines: (1) the models presented are relatively simple yet realistic, empirical, and analytical models; (2) the models do not rely on computationally expensive numerical methods and have been successfully implemented using a commonly available scientific computing platform; and (3) the models consider several essential aspects of the complex physics of hypervelocity meteoroid impacts, which is essential to ensure accurate prediction of the immediate effects of such impacts for lunar structure design. Additionally, this work also includes a wide-ranging parametric analysis that explores and compares the predictions of the physics-based models from an engineering design perspective, encompassing a variety of impact scenarios and impactor-target combinations. The results highlight the practical importance of providing a protective shield, composed of a regolith-like granular material, to mitigate the peak shock pressure sustained by lunar structures in hypervelocity meteoroid impacts. The models, applications, and results presented herein are of immediate relevance to practicing engineers. [ABSTRACT FROM AUTHOR]

In this paper, an innovative hamburger-shaped eddy current damper (HSECD) is presented to mitigate the responses of civil structures subjected to wind excitations. The damper's capacity to dissipate energy is significantly enhanced through a two-phase configuration of permanent magnets (PMs) and two transmission devices: a ball-screw assembly and a bevel gear group. The improved eddy current damper (ECD) solves the problem that the low damping density of traditional ECDs hinders their application to the field of vibration control for civil structures. First, the construction details of this novel HSECD are elaborated, and its principle is discussed through theoretical analysis and numerical simulation. Subsequently, a prototype of the HSECD was fabricated, and cyclic tensile–compressive tests were conducted to investigate its mechanical performance. Furthermore, the temperature effect on the damper's maximum output force was analyzed, and more than 10% performance degradation was detected in tests with a continuous loading of 1,250 s, while the damper performance quickly reached a steady state after a certain decline. A theoretical model of the HSECD was then established to simulate its hysteretic characteristics, and the accuracy was verified by comparing it with the test data, where their energy error was only 1.9%. Finally, the application of the HSECD to both a single-degree-of-freedom (SDOF) simplified system and a jacking engineering system demonstrates its excellent control performance because the reduction ratios of their peak displacement were as high as 31.1% and 40.9%, respectively. These results highlight the significant practical value of the HSECD in mitigating the wind-induced vibrations for engineering structures. [ABSTRACT FROM AUTHOR]

Angle profiles belong to the most common steel profiles used in several types of civil engineering structures, such as in lattice towers. Although, in such towers, they are usually considered as axially loaded (truss) members, an additional bending moment develops due to the eccentricity between the point of load application and the gravity center of the profile. Therefore, this paper focuses on the buckling resistance of single-angle members subjected to combined compression and bending. The investigations have been performed through numerical parametrical studies and have been compared to different normative documents where interaction equations are provided. [ABSTRACT FROM AUTHOR]

Understanding the cracking behaviors and failure mechanisms of soft rocks with existing cracks is crucial in designing rock engineering structures. Hence, we studied the influence of crack parameters, including crack inclination angle, crack number, and crack form, on the strength characteristics and cracking behaviors of silty mudstone using uniaxial compression tests and numerical simulation. The mechanisms of crack initiation, propagation, and coalescence in silty mudstone with preexisting cracks are discussed in this paper. The results showed that the stress-strain curves of silty mudstone with preexisting cracks can be divided into three stages: the load compaction, crack extension, and postpeak damage stages. Preexisting cracks had a weakening effect on the mechanical properties of silty mudstone, and the main order of influence of the various factors was crack inclination angle, crack number, and crack form. The failure mode of silty mudstone with preexisting vertical cracks was mainly composite tensile-shear failure; the failure modes of rocks with single and double cracks were tensile failure, shear failure, and composite tensile-shear failure. The damage process of silty mudstone with preexisting cracks under stress was as follows. The propagation and coalescence of cracks caused cracking of weak surfaces within the rock mass. The cracks propagated along the axial stress direction or preexisting crack direction under different stress states to form macroscopic crack surfaces, which ultimately led to rock mass failure. In addition, the strength characteristics and cracking behaviors of silty mudstone simulated using FLAC3D version 6.0 were consistent with the experimental results. [ABSTRACT FROM AUTHOR]

The article features the two paper selected for the Outstanding Paper Award. The paper by Gianni Bartoli and Michele Betti "Cappella dei Principi in Firenze, Italy: Experimental Analyses and Numerical Modeling for the Investigation of a Local Failure" focuses on structural system in a historical building. The paper by Clay Naito, Daniel Cox, Qi-Song Yu, and Hillary Brooker "Fuel Storage Container Performance during the 2011 Tohoku, Japan, Tsunami" features photographs from field observations.

This paper sheds light on civil facilities that are home to the underrepresented and overlooked population with mental illnesses. More specifically, this paper examines the primary architectural engineering features of psychiatric hospitals from the lens of fire hazards. Psychiatric hospitals rose in popularity in the nineteenth century for individuals deemed unfit to live with the sane population. While they began with good intentions, these hospitals came to represent practices and poor living conditions for mentally ill patients. These conditions, when combined with a wide variety of mental illnesses, resulted in increased risks. One of the most significant risks in psychiatric hospitals was fire—with nearly all psychiatric hospitals examined herein experiencing at least one structural fire despite premier fire control inclusions. A brief history of psychiatric hospitals is presented first, followed by a discussion on various aspects of structural fire design. Then, an analysis of structural fires in psychiatric hospitals throughout the world is performed, and three general and common fire causes and mitigation strategies are presented. Perhaps current and future professionals can better mitigate fire risk in healthcare design by understanding where past architects and designers lacked in designs for vulnerable populations. This paper examines an often overlooked portion of the world's mental health history by shedding light on one of the most significant risks associated with nineteenth- and twentieth-century psychiatric hospitals: fire. A brief introduction to historic mental health facilities and their populations is presented first, followed by a discussion on fire control methods of the past. Then, seven prominent facilities, or asylums, with a history of fire are analyzed for cause and mitigation strategies. As a result, three prominent contributions are discussed and include architectural and structural design, fire mitigation methods, and population characteristics. The goal of this analysis is to increase awareness of the many and broad vulnerabilities of populations (past and present) such as the mentally ill when placed in care facilities. Perhaps current and future professionals can better mitigate fire risk in healthcare design by understanding where past architects and designers lacked in designs for such people. [ABSTRACT FROM AUTHOR]

Architected materials are a new class of materials that interlink practices in architecture and structural engineering to produce materials by conjugation of several simple materials through the interplay between geometry and material properties. Tensegrity structures are composed of struts and cables held in a state of self-stress. With a high strength-to-weight ratio, they provide opportunities for deployable and transportable bridges. Although tensegrity structures are indeterminate, cable damage is challenging to predict and detect a priori, which is aided by a resilient architected material segment as a structural health indicator. The technology of 3D printing complements the development of architected material. Computational studies have shown the effect of coordination number and cross-linking density on the stretch behavior of polymer networks for microscopic deformation scale. This paper presents the relationship between various parameters of multilayered randomized architected material (MLRAM) and its tensile behavior. The randomization of link orientation is to address the unknown direction of the critical force in the strut. A computational model calibrated through experimental testing was developed that mimics the tensile behavior of MLRAM. Using this model, the variation in the tensile behavior in terms of peak tensile capacity and postpeak behavior of MLRAM can be studied for various geometries with specific parameters. From the study, it is observed that the tensile capacity and stiffness of the MLRAM increase with a higher coordination number. The recent advancement of additive manufacturing and 3D printing have provided researchers with the scope to study the feasibility of many difficult geometries and its properties. This is one such study that develops and investigates the tensile properties of a newly developed multilayered randomized architected material (MLRAM). The tensile properties were determined experimentally for centimeter-scale 3D-printed models and a computational model was proposed to replicate the behavior in the linear static region. This novel study provides a preliminary idea of a new concept of architected material that can be extended to a three-dimensional concept in the future. First, the model helps researchers investigate various geometry and design materials with properties as required for specific applications. This proposed MLRAM extended into a three-dimensional material also has the potential to act as visual damage detection indicators that can be incorporated in highly redundant structural systems such as tensegrity structures. [ABSTRACT FROM AUTHOR]

The traditional approach to formulating building codes often is slow and labor-intensive, and may struggle to keep pace with the rapid evolution of technology and domain findings. Overcoming such challenges necessitates a methodology that streamlines the modernization of codal provisions. This paper proposes a machine learning (ML) approach to append a variety of codal provisions, including those of empirical, statistical, and theoretical natures. In this approach, a codal provision (i.e., equation) is analyzed to trace its properties (e.g., engineering intuition and causal logic). Then a ML model is tailored to preserve the same properties and satisfy a collection of similarity and performance measures until declared equivalent to the provision at hand. The resulting ML model harnesses the predictive capabilities of ML while arriving at predictions similar to the codal provision used to train the ML model, and hence it becomes possible to use in lieu of the codal expression. This approach was examined successfully for seven structural engineering phenomena contained within various building codes, including those in North America and Australia. The findings suggest that the proposed approach could lay the groundwork for implementing ML in the development of future building codes. [ABSTRACT FROM AUTHOR]

Predicting the moment-rotation response parameters of semirigid steel connections can be challenging given the many components contributing to the connection's elastic and plastic deformations. This is the case for the popular flush endplate beam-to-column connections (FEPCs). The literature has highlighted the limitations of current analytical, mechanical, and traditional empirical models in providing accurate predictions of the FEPCs' moment-rotation response. Considering this limitation, machine-learning methods have gained wide attention recently in structural engineering applications to address problems associated with complex structural deformation and damage phenomena. To that end, the superior nonlinearity of artificial neural networks (ANN) is employed herein to predict the response characteristics of FEPCs. A large data set of about 200 specimens, collected from past experimental programs, is utilized to train the ANN for predicting the bilinear response of FEPCs including strain hardening. The paper describes the deduction of the response parameters from test data using data fitting, the determination of significant geometric, material, and layout features, the ANN architecture and algorithms, and the accuracy metrics of the new model. The Shapley algorithm is used to explain the inner workings of the model. A computer tool as well as a descriptive guide to the mathematical construction of the ANN are provided to aid with model implementation in practice. [ABSTRACT FROM AUTHOR]

This correction notice addresses errors in the article "Collapse Resistance of Reinforced Concrete Frame Beams under Sustained Loads" by Ghazaleh M. Laleh, Ying Tian, and Sarah L. Orton. The errors occurred when converting imperial units to metric units in the "Bending Moment" section of the paper. The correction involves dividing the numbers on the horizontal axes of Figures 16 and 17, as well as the vertical axis of Figure 18, by 12. Additionally, two values in the last paragraph of this section need to be changed. The corrected figures are provided in the erratum. The purpose of this correction is to ensure the accuracy of the published version. [Extracted from the article]

Six of these papers focus on ultrahigh-performance concrete (UHPC) while five papers focus on high-strength concrete (HSC) or high-strength reinforcing (HSR) steel materials. Yang and Okumus ([11]) describe a parametric numerical investigation on the seismic behavior of UHPC rectangular hollow bridge columns with HSR steel for confinement. In this paper, the results from seven column test specimens demonstrate that the ductility capacity of UHPC-jacketed columns can be increased through textile reinforcing. [Extracted from the article]

Estimating the shear strength of a fiber-reinforced polymer (FRP)–reinforced-concrete (RC) beam is a complex task that depends on multiple design variables. The use of FRP bars has emerged as a promising alternative to diminish the corrosion problems that are associated with steel reinforcement in adverse environments; however, an accurate and reliable method of shear strength prediction is needed to ensure the economical use of materials and robust designs. Several optimized design equations are available in the literature; however, when utilizing these equations a substantial difference is observed between the predicted outcome (Vpred) and the experimental shear strength (Vexp) result. Therefore, this paper presented a novel approach toward implementing machine learning (ML) algorithms to accurately estimate the shear strength of FRP–RC beams. A large database that consisted of 302 shear test results on FRP-reinforced slender concrete beams without stirrup was collected from the literature to formulate the most efficient prediction model. The performance of each ML algorithm model was compared with the existing design provisions and models. The model interpretation was performed through feature importance analysis to explain the model output compared with a black box. The proposed data-driven ML models demonstrated a high level of accuracy and excellent performance and were superior to the existing shear strength models. In addition, a simple graphical user interface (GUI) was developed to aid practicing engineers when estimating shear strength without the need for complicated design procedures. The shear strength of FRP–RC beams is calculated using various design codes and guidelines that are heuristically developed based on previous test results. In general, the developed equations are either mechanics-based or empirical. However, this paper demonstrated that data-driven ML algorithms could generate a more reliable and appropriate prediction of the shear strength of FRP–RC beams. Furthermore, as the database increases, it could be automatically updated, which would result in more accurate and reliable results. Designers and practitioners could conveniently use the developed algorithms for the reliable and quick prediction of the shear strength of FRP–RC beams. In addition, the developed GUI is innovative and user-friendly. It allows users to determine the design shear strength without referring to an existing code by employing ML in conjunction with a large, reliable, and authenticated database to ensure accuracy. This could be important for the structural engineering community when assessing the shear capacity of existing FRP–RC beams. [ABSTRACT FROM AUTHOR]

The article offers presents guidelines on how to review papers published in the "Journal of Structural Engineering." Because the journal has experienced substantial growth, the editor has taken steps to monitor the timeliness of reviews. The editor is calling the authors, reviewers and readers to maintain the excellence of the journal.

The article comments on a study which describes approaches for generating initial ground structures in fields of discrete structural topology optimization including macroelement and macropatch methods. Topics include information on finite-element method (FEM); information on numerical topology optimization which depends on problem specification, and evolutionary structural optimization; and determination of arch bridge as an application of macroelement approach to structural engineering design.

As part of an ongoing effort to update the ground snow load maps in the US, this paper presents an investigation into snow densities for the purpose of predicting ground snow loads for structural engineering design with ASCE 7. Despite their importance, direct measurements of snow load are sparse, compared with measurements of snow depth. As a result, it is often necessary to estimate snow load using snow depth and other readily accessible climate variables. Existing depth-to-load conversion methods, each of varying complexity, are well suited for snow load estimation for a particular region or station network, but none is consistently effective across regions and station networks. In this paper, a random forest regression model is proposed for estimating annual maximum snow loads in the conterminous US that makes use of climate reanalysis data and overcomes the limitations of existing methods. The effectiveness of the random forest model is demonstrated through accuracy comparisons of existing depth-to-load conversion techniques using a compilation of national and state-level data sources. The accuracy comparisons show that the random forest model is competitive for all regions and station networks, whereas other methods are competitive only for certain regions or station networks. These results highlight the feasibility of developing a single depth-to-load conversion method that appropriately characterizes region and climate specific differences in the snow depth–load relationship across the conterminous US. Such universal models are an essential component for creating a unified set of national snow load requirements that eliminate the case study regions currently defined in current national standards. [ABSTRACT FROM AUTHOR]

This paper provides a comprehensive summary of forensic research trends presented in the ASCE's Journal of Performance of Constructed Facilities (JPCF). The paper reports the results of a 24-year analysis of JPCF published literature between 1987 and 2010. The Journal continues to serve as a primary resource for published literature in the field of engineering forensics and provides a recorded history of our recognition and understanding of important lessons learned. Interesting facts were revealed that provide insights for practitioners and academia alike. The investigation indicates a wide participation of engineering disciplines, an increasing number of new topics, innovations, and proactive forensic methodologies, extensive interdisciplinary collaboration, and a significant increase in international contributions. This study may serve as a basis for defining the history and breadth of forensic engineering and for understanding the international relevancy and regional interest in the diverse subject matter. Increased acceptance, dissemination, and participation in forensic engineering is evident and should be encouraged and sustained as part of engineering curricula, investigative research, and professional practice. [ABSTRACT FROM AUTHOR]

Mixed multiple seismic systems (MMSSs) are ideally suited for sustainable seismic design (SSD). MMSSs are combinations of two or more different earthquake-resisting structures (ERSs) that provide lateral support for gravity frameworks. Same-system combinations have been demonstrated to not be suitable for SSD. Regardless of the carbon footprint reduction, unless a structure has been designed for seismic sustainability it would be disposable with greater harm to the environment. Here, design means planning for both seismic resistance as well as post-earthquake realignment and repair (PERR). Earthquakes are random, natural, and dynamic events, whereas PERR is a deliberate, manual, and static process. In SSD the practicality of PERR is as important as the relevance of the theoretical assumptions. In SSD the non-lateral-resisting items are designed not to partake in seismic resistance, nor hinder the realignment process. Additionally, efforts are made to mitigate the P -delta effects that undermine the global strength of the system and oppose the recentering effort. The purpose of this paper is to identify and remedy design flaws and physical issues that prevent MMSSs from achieving seismic sustainability as cost-effectively as possible. Two newly developed technologies, the ladder moment frame (LMF), and the fail-safe (FS) system, as well as a capacity distribution rule together with six simple axioms are introduced. Brief descriptions of LMF and FS are presented in the text. Any structure designed to survive earthquakes is expected to either remain elastic and stable or be capable of post-earthquake realignment and repairs. Sustainable seismic design is a new field of research that promises improved environmental conditions and innovative developments in structural engineering. Regardless of the carbon footprint reduction, unless a structure has been designed for the purpose, it would be disposable with greater harm to the environment. Here, design implies planning for seismic resistance as well as post-earthquake realignment and repairs. The difference between conventional and sustainable seismic design is in the modes of behavior during and after the event. In conventional seismic design, the object is to satisfy code-specified requirements; in sustainable seismic design, the post-earthquake attributes of the system are as important as those during the event. The paper shows that seismic sustainability can be achieved without resorting to untenable costs and technologies. In light of current findings, it is suggested to include post-earthquake realignment and repairs in seismic design guidelines for new construction. [ABSTRACT FROM AUTHOR]

To promote precision installation accuracy of engineering structural components and improve construction quality, point cloud data obtained by 3D laser scanning are widely used in construction quality monitoring. Reasonable parameters are very important to control errors and improve efficiency during the process of 3D laser scanning. Therefore, this paper proposes a random forest-nondominated sorting genetic algorithm (RF-NSGA-II) multiobjective optimization model with an elite strategy. To study the relationship between 3D laser scanning parameters and measurement errors or efficiency, the best scanning parameters are identified. In this paper, high-precision prediction of the relative error and scanning time by 3D laser scanning parameters is achieved by using an RF, and the nonlinear mapping relationship function is obtained, which is used as the objective optimization function. The RF-NSGA-II multiobjective optimization algorithm is developed to optimize the relative error and scanning time, and the scanning time is the shortest under the condition of reasonable relative error. Through this study, we can mainly draw the following conclusions: (1) based on the RF, we can obtain a prediction model of relative error and scanning time with high accuracy, in which the R2 (determination coefficient) value and root mean square error (RMSE) of the relative error prediction model are 0.967 and 0.0277, respectively, and the R2 value and RMSE of the scanning time prediction model are 0.978 and 0.0243, respectively; (2) optimized design parameters for 3D laser scanning of structural components are obtained, including a horizontal incident angle of 90°, an inclination angle of 90°, point cloud density of 3.2 mm, measurement distance of 3 m, resolution of 0.456, and visibility of 8.67 km; and (3) the RF-NSGA-II model developed can effectively reduce the relative error of the 3D laser (by 2.16 mm) and shorten the scanning time (by 148.926 s) compared with the average value. The structural components also meet the requirements in the deviation test. Therefore, the application of the RF-NSGA-II model in the assembly and fabrication of structural components can realize the intellectualization of the production process and improve the precision of the prefabrication of structural components, which has high engineering application value. [ABSTRACT FROM AUTHOR]

The article presents a letter from the editor of "Journal of Structural Engineering" concerning the April 2008 issue. The issue contains expanded versions of several papers presented at the 17th Analysis and Computation Specialty Conference, which was held in St. Louis, Missouri on May 18-21, 2006. The papers focus on computer-based structural analysis.

The purpose of this research is to propose a means to address two issues faced by unmanned aerial vehicles (UAVs) during bridge inspection. The first issue is that UAVs have a notoriously difficult time operating near bridges. This is because of the potential for the navigation signal to be lost between the operator and the UAV. Therefore, there is a push to automate or semiautomate the UAV inspection process. One way to improve automation is by improving UAVs' ability to contextualize their environment through object detection and object avoidance. The second issue is that, to the best of the authors' knowledge, no method has been developed to automatically contextualize detected defects to a structural bridge detail during or after UAV flight. Significant research has been conducted on UAVs' ability to detect defects, like cracks and corrosion. However, detecting the presence of a defect alone does not contextualize its significance or help with an inspector's job to rate specific structural bridge details. This paper outlines a use case for a data set and model to detect critical structural bridge details, providing context and vision for enhancing the autonomous UAV bridge inspection process. Identifying these structural bridge details that require inspection may assist an UAV in path planning and object avoidance in GPS-denied environments. The detection of structural details adds an ability to contextualize defect detection and localize issues to a bridge detail. This also has implications for providing cues to inspectors, in real time, on defect-susceptible areas while UAVs are in flight. The image data set, Common Objects in Context for bridge inspection (COCO-Bridge), for UAV object detection was collected and then trained using deep learning techniques. This data set consists of 774 images and over 2,500 object instances to detect 4 structural bridge details: bearings, cover plate terminations, gusset plate connections, and out-of-plane stiffeners. These details were chosen because they either must be rated by an inspector or checked because they are prone to failure. Methods to economize the predictive capabilities of the model through image augmentation were investigated to extend the performance of the training images. It was concluded that for this domain of data, structural bridge detail images, the mean average precision, and F1 score performance were improved by mirroring the training images along their y -axis. The outcome of this paper was an open-source annotated data set, which can be used in computer vision applications for visual inspection, growing the capabilities of artificial intelligence in structural engineering. [ABSTRACT FROM AUTHOR]

Announces that the American Society of Civil Engineers (ASCE) and the Structural Engineering Institute (SEI) are seeking nominations for their 2006 ASCE and SEI Awards. Objective of the awards; Procedure for submission of nominations; List of prizes.

The collapse of the World Trade Center (WTC) Towers during the terrorist attacks on September 11, 2001, remains one of the most tragic catastrophes in the field of structural engineering. This paper first reviews a mathematical model that explains the process of the total collapse of the Twin Towers and shows that the downward collapse progression below the impacted floors was spontaneous. The model is based on a continuum description of the motion of the crush front and captures various types of energy dissipation during the collapse. The predictions of this model match all the observations, including the video records of the first few seconds of motion of both towers, the seismic records of the collapse durations for both towers, the mass and size distributions of comminuted concrete particles, and the fast expansion of dust clouds during collapse with the booms generated. This catastrophe provoked general interest in other types of progressive collapse of buildings. This is the subject of the second part of this paper, in which a three-dimensional stochastic computational model for the collapse of RC frame buildings is presented. The occurrence probabilities of different collapse patterns are predicted. The model is further extended to investigate the delayed collapse behavior of RC frames. The results of the analysis shed light on the emerging trend of probabilistic analysis and design of structures against progressive collapse. [ABSTRACT FROM AUTHOR]

Calls on nominations for the 2006 American Society of Civil Engineers (ASCE) and Structural Engineering Institute's (SEI) Awards. Objective of the ASCE and SEI Honors and Awards Programs; Alfred Noble Prize; Arthur M. Wellington Prize; Collingwood Prize; J. James R. Croes Medal.

Neural networks (NNs) have seen an increase in popularity in the last few years. As found in several papers, they outperformed other machine learning algorithms and have improved their applicability. NNs have shown potential when working with prediction and detection algorithms by addressing a large variety of problems, such as recognition of heavy machinery, project success prediction, workers' pose assessment, price estimations, and project productivity estimation. To understand the future potential of NNs, we completed a bibliometric analysis of the existing literature, including publications since 2010. The areas in which NNs have been used in construction applications are categorized to understand their connections and underlying architectures. This work found a wider field of applications for NNs in the construction industry than originally known. New architectures such as transformer networks have not been explored fully in construction research but could lead to higher-performing networks. As far as the authors know, this is the first review to solely focus on construction, excluding areas such as structural engineering, indoor climate, occupancy modeling, and energy analysis. The limitations of NNs are discussed, and a path forward is proposed, which includes real-time models and examination of new architectures, which would allow the construction research to fully exploit the potential of NNs. [ABSTRACT FROM AUTHOR]

This paper presents cost-effective guidelines for practicing engineers to design, evaluate, or review the structural design of the sulfur recovery unit (SRU) used in refineries. Extensive efforts have been made over the last few years to develop economical strategies for the process and mechanical design aspects. Limited work is available in practice dealing with structural design of SRUs. This paper bridges the gap and provides economical structural engineering methodologies that can be utilized in practice for the design of SRUs. The sulfur vessel supports are categorized into three systems. Numerical and approximate models are proposed to simplify the analysis and the loading mechanisms during operation and testing. Design examples are also provided for steel pipe racks and vessel support systems that are commonly used in the sulfur recovery units. [ABSTRACT FROM AUTHOR]

In this paper, the seismic design factors for uncoupled composite plate shear walls/concrete filled (C-PSW/CF), a.k.a. SpeedCore, are verified by conducting a study using FEMA methodology. These are the seismic response modification factor, R, the deflection amplification factor, Cd, and the overstrength factor, Ωo; and their values for C-PSW/CF are specified as 6.5, 5.5, and 2.5, respectively. A study was needed, as these factors for uncoupled C-PSW/CFs, included in ASCE 7 since as far back as its 2000 edition, were chosen solely based on the seismic performance of similar structural systems and engineering judgment of the committee members. For this study, four archetypes with planar walls and three archetypes with C-shaped C-PSW/CF walls were chosen. Two different damage measures (DM) were chosen for this study; namely, 3% and 5% maximum interstory drifts. Based on FEMA methodology, all archetypes satisfied the specified performance requirement considering a "good" rating for total system collapse uncertainty (βTOT). [ABSTRACT FROM AUTHOR]

In nature, soil layers possess large variability during their geological process. This variability may also lead to differences in the location and thickness of nonliquefiable and liquefiable soil layers. In practice, the impact of liquefaction on the pile can be ignored at depths greater than 20 m due to high confining stress levels and a lack of liquefaction triggering data. On the other hand, this approach may underestimate design loads in many cases, especially in deep-seated and embedded engineering structures. This paper presents the bending response of piles installed through liquefiable layers located at depths beyond 20 m, and parametric analysis was conducted for a wide range of liquefiable layer thicknesses and depths by using OpenSeesPL (version 3.0.2) software. The numerical results were evaluated considering the inelastic concrete pile behavior under different earthquake records and different peak ground accelerations. The findings show that liquefaction can lead to a failure of piles even at depths greater than 20 m, and thus, a design consideration of piles may require a more comprehensive view considering the liquefiable layer depth and thickness effect. [ABSTRACT FROM AUTHOR]

The random decrement method (RDM) is often used in the experimental modal identification of existing structures. The aim of this study was to improve the applicability of RDM in the identification of multimodal structural damping, taking into account the reduced quality of the random decrement (RD) signature. This goal was achieved by introducing a new approach (Approach 2) to the classic RDM procedure based on linear regression fitting of the extreme values of the RD signature within its limited range in which the stability of this signature is not less than an acceptable threshold level. To quantify the quality of the RD signature, the concept of a stability ratio of the RD signature is introduced. In a case study analyzed in this paper, it was determined that the required value of the stability ratio is at least 92%. The effectiveness of Approach 2 was compared with the classic approach, Approach 1, based on the least-squares curve fitting technique. For this purpose, experimental modal identification of a 292-m steel cable-stayed bridge excited by daily traffic flow was carried out. The results showed improved accuracy of modal damping estimation using Approach 2 for all 11 identified bridge modes, from approximately 1% to 26%, depending on the mode number. To ensure the effectiveness of the RDM analysis, it was recommended to set the parameters of the filtration process, the number of time segments included in the RD signature averaging process, and the triggering level of these time segments. The present study can be applied to the performance of similar modal analyses of complex engineering structures, the response of which is represented by multimode vibrations. [ABSTRACT FROM AUTHOR]

In recent years, substantial efforts have been made to incorporate the nonlinear behavior of joints in frame analysis. In this regard, a well-established component-based model (CBM) is provided in EN 1993-1-8 to capture the nonlinear moment–rotation curve of steel beam-column joints. In this paper, to extend the design approach in EN 1993-1-8 to steel beam-to-reinforced concrete column (RCS) joints, a simple mechanical model is first developed to determine the moment resistance of RCS joints. The proposed model can predict two different failure modes of RCS joints and yields better accuracy and consistency compared to the current design method for such joints. After determining the joint moment resistance, an appropriate CBM is developed to simulate the nonlinear moment–rotation response of RCS joints. The proposed CBM can capture the moment–rotation behavior of RCS joints at elastic, transitional, and ultimate states. The initial rotational stiffness of RCS joints can be easily calculated based on the proposed CBM. This is particularly important in the frame analysis as the beam-column joint can be classified as a rigid, semirigid, or pinned joint based on the initial rotational stiffness. The derivations are discussed in detail, followed by verifications of the proposed CBM. Compared to the experimental results, the proposed CBM shows reasonable accuracy in predicting the moment–rotation behavior of RCS joints. Most importantly, the numerical procedure of the proposed CBM can be implemented by a spreadsheet method, which provides a simple and robust means for structural engineers to obtain the mechanical properties of RCS joints. [ABSTRACT FROM AUTHOR]

In the last few decades, structural health monitoring (SHM) has proven a helpful tool to support the maintenance and management of civil infrastructure. However, typical measurement networks are expensive and require considerable initial efforts. The user-friendliness and interpretability of the outcome of SHM systems are crucial factors in motivating infrastructure owners and decision-makers to sustain their costs. For this reason, simple algorithms that provide structural parameters with direct physical interpretability for professionals familiar with the typical quantities involved in structural engineering are still the most used in field applications. This paper proposes an original method to identify curvature influence lines of bridges and viaducts only using the structural acceleration response induced by vehicular loads. Acceleration time histories collected at sparse locations through standard accelerometers are employed. In contrast to SHM approaches based on modal parameters, the proposed method does not need strict synchronization, thus being suitable for wireless and low-cost monitoring solutions. Identified influence lines are used to define a spatially dense damage indicator for accurate localization of structural anomalies with a clear physical meaning. Experimental results obtained for a steel truss bridge analyzed in different damage conditions prove the efficacy of the proposed method for situations where modal-based approaches may fail. [ABSTRACT FROM AUTHOR]

Lists papers of interest published in other journals of the American Society of Civil Engineers. "A Mixed Integer Nonlinear Least-Squares Problem for Damage Detection in Truss Structures," by Y. Araki and Y. Miyagi; "Long-Term Performance Monitoring of the Tech 21 All-Composite Bridge," by D. N. Farhey; "Tangent Geometric Stiffness of Inclined Cables Under Self-Weight," by A. D. Kiureghian and J. L. Sackman.

Although steel single angle sections are commonly used as beams to support distributed loads which cause biaxial bending and torsion, their behavior may be extremely complicated, and the accurate prediction of their strengths very difficult. Further, many design codes do not have any design rules for torsion, while some recommendations are unnecessarily conservative, or are of limited application, or fail to consider some effects which are thought to be important. This paper is one of a series on the behavior and design of single angle section steel beams. Two previous papers have studied the biaxial bending behavior of restrained beams, a third has studied the lateral buckling of unrestrained beams, and a fourth the biaxial bending of unrestrained beams. In each paper, simple design methods have been developed. In this present paper, an approximate method of predicting the second-order deflections and twist rotations of steel equal angle beams under major axis bending and torsion is developed. This method is then used to determine the approximate maximum biaxial bending moments in such beams, which are then used with the section moment capacity proposals of the first paper of the series and the lateral buckling proposals of the third paper to approximate the member capacities. This method is extended to steel unequal angle beams in a companion paper. [ABSTRACT FROM AUTHOR]

The number of studies on ultrahigh-performance concrete (UHPC) or ultrahigh-performance fiber-reinforced concrete (UHP-FRC) for more resilient and sustainable reinforced concrete (RC) structures has rapidly increased in recent years due to the superior mechanical and durability properties of UHPC. The application of UHPC as a replacement for conventional concrete materials in various RC elements necessitates a thorough understanding of the structural behavior of the reinforced UHPC (R/UHPC) components under various types of loadings. This paper presents a systematic review of the state-of-the-art developments in R/UHPC elements. It addresses various topics including beams, columns, beam–column joints, shear walls, bridges, structural retrofitting, and applications such as seismic and impact. Due to the ultrahigh tensile, compressive, and bond strengths, unique strain-hardening behavior, and ductility of UHPC, R/UHPC structures may exhibit substantially different behavior than conventional RC structures at both the component and system levels. This implies that particular attention must be paid when design and analysis approaches for conventional RC elements are applied to R/UHPC elements, and suggests that developing new design philosophies is warranted to take advantage of UHPC's unique mechanical properties. The present paper summarizes the developments in analysis and design approaches for R/UHPC elements under axial forces, shear forces, and bending moments, and highlights the advantages and limitations of these approaches. Important design considerations for effectively utilizing UHPC in structural elements are also suggested. In addition to normal-strength steel reinforcing bars, the potential for reinforcing UHPC with high-strength steel bars, fiber-reinforced polymer components, and structural steel shapes is discussed based on the results of pioneering studies. Finally, this paper identifies challenges and suggests future directions for research on UHPC in structural engineering. [ABSTRACT FROM AUTHOR]

Soft-core sandwich structures subjected to coplanar compression loading might exhibit wrinkling behaviors, which will reduce significantly the support capability of the structure. In order to prevent the wrinkling behaviors of sandwich structures, this work attempts to improve stiffness of face sheets reinforced by carbon nanotubes (CNTs). To achieve such a goal, the following work is to be required. First, an equivalent single-layer model will be proposed to accurately analyze the wrinkling behaviors of sandwich structures because only layerwise models possess the capability to accurately predict wrinkling behaviors of sandwich structures, but these models are often computationally expensive. Second, the influence of distributions of the CNTs through thickness on the buckling and wrinkling behaviors for the sandwich beams will be investigated in detail. Moreover, the translation mechanism between the buckling deformation and the wrinkling deformation has been also explored. The proposed model has been verified by using the quasi three-dimensional (3D) elasticity solutions and the 3D finite-element results (3D-FEM). Third, by selecting the proper distributions of the CNTs through the thickness of sandwich structures, the wrinkling behaviors of sandwich structures can be effectively prevented. Thus, a scheme resisting wrinkling deformation of sandwich structures has been proposed, which can provide a reference for other investigators. Sandwich structures are extensively used in many engineering applications due to their high strength to weight ratios and ease of manufacture. However, sandwich structures subjected to in-plane compressive loads might encounter wrinkling failure. In practical applications, this phenomenon is so common, but when it occurs, the sandwich structures will become unstable and cannot withstand higher loads. Therefore, it is crucial to take effective measures to avoid the occurrence of such unfavorable phenomena. To this end, a strategy was presented, where carbon nanotubes are proposed to be added to the face-sheet of sandwich structures. In order to verify the effectiveness of this method, a computational model was also proposed to analyze the wrinkling behaviors. By comparing with the 3D-FEM results of computer simulations, it was proven that the proposed model is correct and effective. In addition, it was found that different volume fractions and distributions of carbon nanotubes have the different influences resisting wrinkling deformation. In practical applications, structural engineers might get some inspirations to avoid the instability of sandwich structures from the research results of this paper. [ABSTRACT FROM AUTHOR]

Presents news briefs on forensic engineering as of November 1999. Recipient of the 1998 ASCE Technical Council on Forensic Engineering's Outstanding Paper award; Nominees for the award; Award received by doctor John M. Hanson; Organizations which formed the SAC Joint Venture.