Super-long span bridges demand high design requirements and involve many difficulties when constructed, which is an important indicator to reflect the bridge technical level of a country. Over the past three decades, a large percentage of the new long-span bridges around the world were built in China, and thus, abundant technological innovations and experience have been accumulated during the design and construction. This paper aims to review and summarize the design and construction practices of the superstructure, the substructure, and the steel deck paving of the long-span bridges during the past decades as well as the current operation status of the existing long-span bridges in China. A future perspective was given on the developing trend of high-speed railway bridge, bridge over deep-sea, health monitoring and maintenance, intellectualization, standard system, and information technology, which is expected to guide the development direction for the construction of future super long-span bridges and promote China to become a strong bridge construction country.

Modern long-span space structures, developed during the 1970s and 1980s, are light and effective structures based on new technologies and light-weight high-strength materials, such as membranes and steel cables. These structures include air-supported membrane structures, cable-membrane structures, cable truss structures, beam string structures, suspen-domes, cable domes, composite structures of cable dome and single-layer lattice shell, Tensairity structures and so forth. For the premodern space structures widely used since the mid-twentieth century (such as thin shells, space trusses, lattice shells and ordinary cable structures), new space structures have been developed by the combination of different structural forms and materials. The application of prestressing technology and the innovation of structural concepts and configurations are also associated with modern space structures, including composite space trusses, open-web grid structures, polyhedron space frame structures, partial double-layer lattice shells, cable-stayed grid structures, tree-type structures, prestressed segmental steel structures and so forth. This paper provides a review of the structural characteristics and practical applications in China of modern rigid space structures, modern flexible space structures and modern rigid-flexible combined space structures.

This paper presents a comprehensive review of modeling of alkali-silica reaction (ASR) in concrete. Such modeling is essential for investigating the chemical expansion mechanism and the subsequent influence on the mechanical aspects of the material. The concept of ASR and the mechanism of expansion are first outlined, and the state-of-the-art of modeling for ASR, the focus of the paper, is then presented in detail. The modeling includes theoretical approaches, meso- and macroscopic models for ASR analysis. The theoretical approaches dealt with the chemical reaction mechanism and were used for predicting pessimum size of aggregate. Mesoscopic models have attempted to explain the mechanism of mechanical deterioration of ASR-affected concrete at material scale. The macroscopic models, chemo-mechanical coupling models, have been generally developed by combining the chemical reaction kinetics with linear or nonlinear mechanical constitutive, and were applied to reproduce and predict the long-term behavior of structures suffering from ASR. Finally, a conclusion and discussion of the modeling are given.

In recent few years, significant improvement has been made in developing largescale 3D printers to accommodate the need of industrial-scale 3D printing. It is of great feasibility to construct structural components and buildings by means of 3D concrete printing. The major issues of this innovative technique focus on the preparation and optimization of concrete materials which possess favourable printable properties as well as the measurement and evaluation methods of their workability. This paper firstly introduces three largescale 3D printing systems that have been successfully applied in construction industry. It then summarizes the commonly used raw materials in concrete manufacturing. Critical factors that should be particularly controlled in material preparation are specified. Easy-extrusive, easy-flowing, well-buildable, proper setting time and low shrinkage are significant for concrete mixture to meet the critical requirements of a freeform construction process. Thereafter, measuring methods that can be employed to assess the fresh and hardened properties of concrete at early stages are suggested. Finally, a few of evaluation methods are presented which may offer certain assistance for optimizing material preparation. The objective of this work is to review current design methodologies and experimental measurement and evaluation methods for 3D printable concrete materials and promote its responsible use with largescale 3D printing technology.

Effective evaluation of rock permeability is required in different energy, engineering and environmental projects. Although much research has been conducted on rock permeability, it is still one of the most difficult tasks for practicing rock engineers to accurately determine rock permeability. Based on a comprehensive literature review, this paper outlines the key aspects of rock permeability by presenting the representative values of the permeability of different rocks, describing the empirical and semi-empirical correlations for estimating the permeability of rocks, and discussing the main factors affecting the permeability of rocks. The factors discussed include stress, depth, temperature, and discontinuity intensity and aperture. This paper also highlights the scale effect on rock permeability, interconnectivity of discontinuities, and anisotropy of rock permeability. This paper provides the fundamental and essential information required for effective evaluation of rock permeability.

The first “modern” type of vehicular bridge was built in Hong Kong China in the 1920s. The need for an efficient transportation system to cope with population growth and enable economic development has demanded the construction of more and more bridges since the middle of the 20th century. By 2007, Hong Kong had a total of about 1300 vehicular bridges. Four of these bridges, including the Tsing Ma Bridge, Kap Shui Mun Bridge, Ting Kau Bridge, and the cable-stayed bridge on the Hong Kong- Shenzhen Western Corridor, are considered to be major bridges supported by cables. Currently, the Stonecutters Bridge on Route No. 8 is under construction and is expected to be completed in late 2009. At the same time, the Hong Kong-Zhuhai-Macao Bridge will be in its detailed design stage soon. While efforts have been made by bridge builders to construct these giant structures, the upkeeping of these valuable assets at a high standard and ensuring their continuous functioning and performance during their intended lifespans will be another important task for bridge engineers. Wind and structural health monitoring system (WASHMS) will play a key role in this respect.

Fire resistance rating of light gauge steel frame (LSF) wall systems is obtained from fire tests based on the standard fire time-temperature curve. However, fire severity has increased in modern buildings due to higher fuel loads as a result of modern furniture and light weight constructions that make use of thermoplastics materials, synthetic foams and fabrics. Some of these materials are high in calorific values and increase both the spread of fire growth and heat release rate, thus increasing the fire severity beyond that of the standard fire curve. Further, the standard fire curve does not include a decay phase that is present in natural fires. Despite the increasing usage of LSF walls, their behavior in real building fires is not fully understood. This paper presents the details of a research study aimed at developing realistic design fire curves for use in the fire tests of LSF walls. It includes a review of the characteristics of building fires, previously developed fire time-temperature curves, computer models and available parametric equations. The paper highlights that real building fire time-temperature curves depend on the fuel load representing the combustible building contents, ventilation openings and thermal properties of wall lining materials, and provides suitable values of many required parameters including fuel loads in residential buildings. Finally, realistic design fire time-temperature curves simulating the fire conditions in modern residential buildings are proposed for the testing of LSF walls.

Bridge girders exposed to aggressive environmental conditions are subject to time-variant changes in resistance. There is therefore a need for evaluation procedures that produce accurate predictions of the load-carrying capacity and reliability of bridge structures to allow rational decisions to be made about repair, rehabilitation and expected life-cycle costs. This study deals with the stability of damaged steel I-beams with web opening subjected to bending loads. A three-dimensional (3D) finite element (FE) model using ABAQUS for the elastic flexural torsional analysis of I-beams has been used to assess the effect of web opening on the lateral buckling moment capacity. Artificial neural network (ANN) approach has been also employed to derive empirical formulae for predicting the lateral-torsional buckling moment capacity of deteriorated steel I-beams with different sizes of rectangular web opening using obtained FE results. It is found out that the proposed formulae can accurately predict residual lateral buckling capacities of doubly-symmetric steel I-beams with rectangular web opening. Hence, the results of this study can be used for better prediction of buckling life of web opening of steel beams by practice engineers.

Frequent failures due to foreign particle impacts are observed in compressor blades of the interceptor fighter MIG-23 aircraft engines in the Ethiopian air force, supplied by the Dejen Aviation Industry. In this paper, we made an attempt to identify the causes of failure and hence recommend the suitable materials to withstand the foreign particle impacts. Modal and stress analysis of one of the recently failed MIG-23 gas turbine compressor blades made up of the following Aluminum based alloys: 6061-T6, 7075-T6, and 2024-T4, has been performed, apart from the impact analysis of the rotor blades hit by a granite stone. The numerical results are correlated to the practical observations. Based on the modal, stress and impact analysis and the material properties of the three considered alloys, alloy 7075-T6 has been recommended as the blade material.

This paper presents a constitutive model based on Ramberg-Osgood equation to describe the hysteresis material behavior of structural carbon steel with nominal yield strength between 235 to 420 N/mm². The proposed model was calibrated against a series of cyclic material tests with strain amplitude varying from 0.5% to 2.0%. A simple relationship between the modular parameter K and the yield strength f_y was proposed. The calibrated Ramberg-Osgood model revealed excellent agreement with the experimental results and captured further the experimental behavior of test specimens with nominal yield strength of 460 N/mm². The proposed constitutive model was also adopted in conjunction with the combined kinematic/isotropic materials description in ABAQUS to mimic a full scale experimental test under cyclic loading. The numerical results revealed close agreement with the experimental observations.

This paper presents the results of a research project aimed at providing standard circular web openings to the popular precast pretensioned inverted T-beam. Opening size and placement and required materials strengths were investigated. In this paper the nonlinear analysis and design of simply supported pretensioned inverted T-beam with circular web openings are presented. Two design parameters are varied: opening location and number of openings. The results from nonlinear finite element analysis were substantiated by test results from five pretensioned inverted T-beams with web opening and one solid beam. Good agreement is shown between the theoretical and the experimental results. The test results obtained from this investigation show that the performance of the specimens with web openings is almost identical to that of the specimen without web openings. A simple design method for pretensioned inverted T-beam with circular web openings is proposed.

A mechanical model recently developed for the shear strength of slender reinforced concrete beams with and without shear reinforcement is presented and extended to elements with uniformly distributed loads, specially focusing on practical design and assessment in this paper. The shear strength is considered to be the sum of the shear transferred by the concrete compression chord, along the crack, due to residual tensile and frictional stresses, by the stirrups and, if they exist, by the longitudinal reinforcement. Based on the principles of structural mechanics simple expressions have been derived separately for each shear transfer action and for their interaction at ultimate limit state. The predictions of the model have been compared to those obtained by using the EC2, MC2010 and ACI 318-08 provisions and they fit very well the available experimental results from the recently published ACI-DAfStb databases of shear tests on slender reinforced concrete beams with and without stirrups. Finally, a detailed application example has been presented, obtaining each contributing component to the shear strength and the assumed shape and position of the critical crack.

On June 24, 2021, a 40-year-old reinforced concrete flat plate structure building in Miami suffered a sudden partial collapse. This study analyzed the overall performance and key components of the collapsed building based on the building design codes (ACI-318 and GB 50010). Punching shear and post-punching performances of typical slab-column joints are also studied through the refined finite element analysis. The collapse process was simulated and visualized using a physics engine. By way of these analyses, weak design points of the collapsed building are highlighted. The differences between the reinforcement detailing of the collapsed building and the requirements of the current Chinese code are discussed, together with a comparison of the punching shear and post-punching performances. The simulated collapse procedure and debris distribution are compared with the actual collapse scenes.

This paper presents the results of nonlinear finite element analyses conducted on stainless steel shear links. Stainless steels are attractive materials for seismic fuse device especially for corrosion-aware environment such as coastal regions because they are highly corrosion resistant, have good ductility and toughness properties in combination with low maintenance requirements. This paper discusses the promising use of AISI 316L stainless steel for shear links as seismic fuse devices. Hysteresis behaviors of four stainless steel shear link specimens under reversed cyclic loading were examined to assess their ultimate strength, plastic rotation and failure modes. The nonlinear finite element analysis results show that shear links made of AISI 316L stainless steel exhibit a high level of ductility. However, it is also found that because of large over-strength ratio associated with its strain hardening process, mixed shear and flexural failure modes were observed in stainless steel shear links compared with conventional steel shear links with the same length ratio. This raises the issue that proper design requirements such as length ratio, element compactness and stiffener spacing need to be determined to ensure the full development of the overall plastic rotation of the stainless steel shear links.

In this paper, the mechanical behavior of sand, was systematically described and modeled with a elastoplastic model proposed by Zhang et al. [1]. Without losing the generality of the sand, a specific sand called as Toyoura sand, a typical clean sand found in Japan, has been discussed in detail. In the model, the results of conventional triaxial tests of the sand under different loading and drainage conditions were simulated with a fixed set of material parameters. The model only employs eight parameters among which five parameters are the same as those used in Cam-clay model. Once the parameters are determined with the conventional drained triaxial compression tests and undrained triaxial cyclic loading tests, then they are fixed to uniquely describe the overall mechanical behaviors of the Toyoura sand, without changing the values of the eight parameters irrespective of what kind of the loadings or the drainage conditions may be. The capability of the model is discussed in a theoretical way.

In the recent years, the phase field method for simulating fracture problems has received considerable attention. This is due to the salient features of the method: 1) it can be incorporated into any conventional finite element software; 2) has a scalar damage variable is used to represent the discontinuous surface implicitly and 3) the crack initiation and subsequent propagation and branching are treated with less complexity. Within this framework, the linear momentum equations are coupled with the diffusion type equation, which describes the evolution of the damage variable. The coupled nonlinear system of partial differential equations are solved in a ‘staggered’ approach. The present work discusses the implementation of the phase field method for brittle fracture within the open-source finite element software, FEniCS. The FEniCS provides a framework for the automated solutions of the partial differential equations. The details of the implementation which forms the core of the analysis are presented. The implementation is validated by solving a few benchmark problems and comparing the results with the open literature.

Intersecting connection plays an important role in the new diagrid structural system for high-rise buildings. To investigate the static behavior of the intersecting connection of concrete-filled steel tubular (CFST) columns, a typical reduced-scale planner connection specimen is tested under monotonic axial compression. The failure modes, force mechanism and bearing capacity of intersecting CFST connections are analyzed further in the follow-up numerical simulation, considering influences of intersecting angle, elliptical plate and ring plate. Test and simulation results prove that, intersecting connection can develop fully plastic deformation and provide sufficient bearing capacity. Parametric analysis indicates that bearing capacity of planar intersecting CFST connection mainly depends on intersecting angle and thickness of elliptical plate, while the ring plate affects that little. Capacity estimation method for planar intersecting CFST connection is proposed basing on the capacity of the critical section which is located near intersecting center for a distance of steel tube radius, and the design suggestions is provided in the end of this paper.

In this paper, an experimental investigation is conducted to study the mechanical behavior of saturated natural loess, saturated natural filling in ground fissure and their corresponding saturated remoulded soils under three consolidated undrained triaxial stress tests, namely, conventional triaxial compression test (CTC), triaxial compression test (TC) and reduced triaxial compression test (RTC). The test results show that stress-strain relation, i.e. strain-softening or strain-hardening, is remarkably influenced by the structure, void ratio, stress path and confining pressure. Natural structure, high void ratio, TC stress path, RTC stress path and low confining pressures are favorable factors leading to strain-softening. Excess pore pressure during shearing is significantly affected by stress path. The tested soils are different from loose sand on character of strain-softening and are different from common clay on excess pore water pressure behavior. The critical states in p′– q space in CTC, TC and RTC tests almost lie on one line, which indicates that the critical state is independent of the above stress paths. As for remoulded loess or remoulded filling, the critical state line (CSL) and isotropic consolidation line (ICL) in e-log p′ space are almost straight, while for natural loess or natural filling, in e-log p′ space there is a turning point on the CSL, which is similar to the ICL.

Opened to traffic in August 2004, the Rion-Antirion Bridge crosses the Gulf of Corinth near Patras in western Greece. It consists of an impressive multi cable-stayed span bridge connected to the land by two approaches.

An exceptional combination of physical conditions made this project quite unusual: high water depth, deep strata of weak soil, strong seismic activity and fault displacements. In addition a risk of heavy ship collision had to be taken into account.

The structure has been designed in view of challenging severe earthquakes and ensuring the everyday serviceability of the link as well. To make the bridge feasible, innovative techniques had to be developed: The strength of the in situ soil has been improved by means of inclusions; the bridge deck has been suspended on its full length, and therefore isolated as much as it can be.

Study of beach morphology has been one of the most important issues in coastal engineering research projects. Because of the existence of two important coastal areas located in the north and south parts of the Iran, in the present study an analysis of the coastal zone behaviour is made. Bed level elevations are measured and compared with the theoretical equilibrium profile. It is shown that the behaviour of the coastal zone in the region is consistent with the Dean (1991) equilibrium profile. In the next stage, following extensive investigations, the bed level changes due to arise in sea level at different locations in the surf zone are estimated. The mechanism of beach re-treatment due to a rise in sea level is considered based on the simplified model of Dean (1991) in which the mass balance of the sediments is taken into account. Comparison of the equilibrium profiles for different cases of sea level rise, clearly shows that because of the sediment transport induced by the fluctuation of the water level, the beach profile in the surf zone changes accordingly resulting in an erosion in the inner region of the surf zone and an accumulation of sediments towards the offshore.

The vibrations and noises of elevated railway structures have been cause for concern due to their effects on the environment and the people living near elevated lines. In this paper, the main structural features of some new elevated bridges and station hall were introduced. The generation mechanism of vibrations and noise of elevated structures induced by trains were investigated. The noise induced by different types of elevated bridges, their influences on the environment and the theoretical method for the analysis of structure borne noise was analyzed. Finally, several field measurements on train induced noises at the platforms of elevated subway stations and bridges were presented.

This paper is categorized into two parts. (1) A frame work to design the aircraft wing structure and (2) analysis of a morphing airfoil with auxetic structure. The developed design frame work in the first part is used to arrive at the sizes of the various components of an aircraft wing structure. The strength based design is adopted, where the design loads are extracted from the aerodynamic loads. The aerodynamic loads acting on a wing structure are converted to equivalent distributed loads, which are further converted point loads to arrive at the shear forces, bending and twisting moments along the wing span. Based on the estimated shear forces, bending and twisting moments, the strength based design is employed to estimate the sizes of various sections of a composite wing structure. A three dimensional numerical model of the composite wing structure has been developed and analyzed for the extreme load conditions. Glass fiber reinforced plastic material is used in the numerical analysis. The estimated natural frequencies are observed to be in the acceptable limits. Furthermore, the discussed design principles in the first part are extended to the design of a morphing airfoil with auxetic structure. The advantages of the morphing airfoil with auxetic structure are (i) larger displacement with limited straining of the components and (ii) unique deformation characteristics, which produce a theoretical in-plane Poisson’s ratio of −1. Aluminum Alloy AL6061-T651 is considered in the design of all the structural elements. The compliance characteristics of the airfoil are investigated through a numerical model. The numerical results are observed to be in close agreement with the experimental results in the literature.

Modern bridge building is much more than concrete, steel and money. The overall socioeconomic impact, influence on people migration, traffic, use of primary materials, safety of construction impact on the environment, energy, risk scenarios, health, and most relevant now: climate and CO₂ emissions, are among the parameters which enter into the decision process at the overall holistic conceptual level, the more detailed level of selection of bridge sites, and selection of bridge types as well as construction methods and selection of materials and products.

The paper illustrates these dilemmas and illustrates by specific examples how this complicated decision process can be managed and structured in order to arrive at an overall satisfactory solution for design, construction and maintenance throughout the lifetime (life cycle) to these sometimes contradictory parameters and requirements.

This paper presents the design guide based on analytical, numerical and experimental investigation of Steel-concrete-steel (SCS) sandwich structural members comprising a lightweight concrete core with density ranged from 1300 to 1445 kg/m³ subjected to static, impact and blast loads. The performance of lightweight sandwich members is also compared with similar members with normal weight concrete core and ultra high strength concrete core (f_c = 180 MPa). Novel J-hook shear connectors were invented to prevent the separation of face plates from the concrete core under extreme loads and their uses are not restricted by the concrete core thickness. Flexural and punching are the primary modes of failure under static point load. Impact test results show that the SCS sandwich panels with the J-hook connectors are capable of resisting impact load with less damage in comparison than equivalent stiffened steel plate panels. Blast tests with 100 kg TNT were performed on SCS sandwich specimens to investigate the key parameters that affect the blast resistance of SCS sandwich structure. Plastic yield line method is proposed to predict the plastic capacity and post peak large deflection of the sandwich plates. Finally, an energy balanced model is developed to analyze the global behavior of SCS sandwich panels subjected to dynamic load.

In this paper, a dynamic analysis model of an elevated bridge with ladder tracks under moving train load is established. The whole process of a train running through an elevated bridge at different speeds is simulated. The dynamic responses of the elevated bridge with ladder track and the running safety and comfort index of train vehicles are evaluated. Compared with the dynamic responses of an elevated bridge with ordinary non-ballasted slab track, the ladder track’s effect on reducing the vibration of an elevated bridge is analyzed. The analysis results show that the ladder track has good vibration reduction characteristics as compared to ordinary non-ballasted track.

This paper reports on modern developments related to nanotechnology of cement and concrete. Recent advances in instrumentation and design of advanced nano-composite materials is discussed. New technological directions and historical milestones in nanoengineering and nanomodi?cation of cement-based materials are presented. It is concluded that there is a strong potential of nanotechnology to improve the performance of cement-based materials.

In view of China’s development trend of green building and building industrialization, based on the emerging requirements of the structural engineering community, the development and proposition of novel resource-saving high-performance steel-concrete composite structural systems with adequate safety and durability has become a kernel development trend in structural engineering. This paper provides a state of the art review of China’s cutting-edge research and technologies in steel-concrete composite structures in recent years, including the building engineering, the bridge engineering and the special engineering. This paper summarizes the technical principles and applications of the long-span bi-directional composite structures, the long-span composite transfer structures, the comprehensive crack control technique based on uplift-restricted and slip-permitted (URSP) connectors, the steel plate concrete composite (SPCC) strengthen technique, and the innovative composite joints. By improving and revising traditional structure types, the comprehensive superiority of steel-concrete composite structures is well elicited. The research results also indicate that the high-performance steel-concrete composite structures have a promising popularizing prospect in the future.

The concept of sustainability is described in this paper using a single sustainable principle, two goals of sustainable development, three dimensions of sustainable engineering, four sustainable requirements and five phases of sustainable construction. Four sustainable requirements and their practice in China are discussed in particular. The safe reliability of bridges is first compared with the events of bridge failure in China and in the rest of the world and followed by structural durability, including the cracking of concrete cable-stayed bridges, deflection of concrete girder bridges and fatigue cracks of orthotropic steel decks. With respect to functional adaptability, lateral wind action on vehicles and its improvement are introduced regarding a sea-crossing bridge located in a typhoon-prone area. The Chinese practice of using two double main span suspension bridges and a twin parallel deck cable-stayed bridge is presented in discussing the final sustainable requirement: capacity extensibility.

The paper presents a numerical study on the undrained lateral response of a single, free-head, reinforced concrete pile in soft clays. Soil conditions simulating normally consolidated clays are examined—undrained shear strength increasing with depth—and the pile-soil interaction under static lateral loading is analyzed. The nonlinear p?y curves proposed in literature for soft clays are imported into a beam-on-nonlinear-Winkler-foundation simulation in order to predict the pile head lateral load—displacement curve and the distribution of the horizontal displacement and bending moment along the pile. The striking differences among these methods require further investigation via 3D finite element analyses. The determination of the ultimate soil resistance p_ult from the results of the finite element analyses aims at providing the estimation of a range of values for the ultimate soil resistance coefficient N_p with depth and the comparison of the derived values to the corresponding ones proposed by existing methodologies.

The present study deals with the study of the velocity distribution and the separation phenomenon of flow of air over a two dimensional backward facing step. The flow of air over a backward facing step has been investigated numerically using FLUENT. Flow simulation has been carried out in a backward facing step having an expansion ratio (ratio of the height before and after the step) of 1:1.94 and the results obtained are compared with the published experimental results. Comparison of flow characteristics between steps with three different transitions is made. The variation of reattachment length for all the three cases are analyzed for wide range of Reynolds number ranging from 100 to 7000 which covers the laminar, transition and turbulent flow of air. Simulation of the flow over steps with expansion ratios of 1:1.24, 1:1.38, 1:1.47, 1:1.53, 1:1.94, 1:2.20 are also carried out to examine the effect of different expansion ratios on the reattachment length. It is found that the primary reattachment length increases with increase in the expansion ratio. The primary reattachment length at the bottom wall downstream of the step is minimum for the step with round edged transition and maximum for the step with a vertical drop transition.