Explore the vast range of titles available.

Ignoring the effect of a concrete core on bearing performance, the current design of prestressed concrete cylinder pipes (PCCPs) under internal water pressure only focuses on the fracture of prestressed steel wire, while the complexity of the AWWA C304 design method leads to a strong dependence on software that cannot be sufficiently mastered by the designers. In view of these issues, a simplified limit-state design process was induced to eliminate a large number of iterative operations and was verified by a three-dimensional finite element model (FEM) with a prototype test of PCCPs under internal water pressure. Meanwhile, the bearing performance of PCCPs was investigated using the parametric simulations of the FEM. The results showed that the cross-sectional area of the prestressed steel wire is higher by about 10% than that designed using the AWWA C304 method. The FEM provides a complete evolution process of the mechanical response of the structural constituents and simulates the strain mutation phenomenon of the prototype test well. The internal water pressure of the PCCPs designed using the simplified limit-state design process has enough safety to reach 4.7 times the working pressure at serviceability and 5.5 times the pressure at the ultimate limit state. A burst in the PCCPs took place under an internal pressure greater than 6.75 times the working pressure. The result of the FEM shows that an increase in the tensile strength of the concrete core is of great significance for improving the bearing performance of the PCCPs.

Soil nailing is a versatile construction technique used for retaining structures, offshore structures, structures rehabilitation, and stabilizing natural as well as man-made earth slopes. This method was initially evolved in Europe and recognized in various provinces. This research investigates the relationship between uniform vertical and uniform horizontal loading on soil slopes to gain new insights into the effectiveness of soil nailing in stabilizing earth slopes. This study used a novel numerical investigation to determine the maximum factor of safety (FOS) at various nail inclinations of 0°, 5°, 10°, 15°, 20°, and 25° with the horizontal plane. To evaluate the effectiveness of the soil nail system for slope stabilization, the study considered significant limiting factors by using the limit state design (LSD) approach. In addition, the numerical method for identifying slope displacement, mathematical modelling for identifying nail displacement within soil slope, and experimental investigation in the laboratory were carried out in this study. The investigation's findings show that soil nailing is the more effective technique for slope stabilization. The 15° nail inclination with the horizontal plane produced the best results in terms of stability and FOS. Furthermore, considering the critical limiting factors, an inclination of 15° for soil nails exhibits optimal effectiveness in strengthening the stability of a vertical cut soil slope. This inclination angle allows for efficient load transfer and distribution and decreases the risk of slope failure. Overall, the 15° nail inclination with the horizontal plane provides valuable insights and an increased FOS.

Steel I beams or girders with sinusoidal corrugated profile webs have become popular in the recent development of the steel structural designs, since corrugated-web beams (CWBs) can provide better performance in terms of less deformation and more stability against buckling failure. It is verified in previous research that CWBs can be considered as an alternative to replace normal beams in the structural designs with their numerous favourable features. Since CWBs are being used as the main structural elements, it is apparent that some essential practical properties of this type of beams should be studied, where the prediction of the shear capacity is one of the most significant design aspects that should be accurately investigated. Calculations to the design formulas from other standards and several finite element simulations have been carried out to compare the differences in obtained results and to find an adequate approach to calculate the shear capacity of CWBs for the Australian civil engineering community. Ultimate Limit State design theory has been utilised in conjunction with AS4100 (2017) along with linear analysis in SAP2000. By comparing the results of the theoretical calculations and numerical simulations, it has been concluded that the highly formed equations presented by EN 1993-1-5 (Design of Steel Structures Part 1–5: Plated Structural Elements, Eurocode 3, Brussels, 2006), Hancock et al. (2012) could well estimate the shear capacity constraining requirements and rules in accordance with Australian standards, which can be adequately used in Australian structural design fields.

Steel I girders with corrugated webs are appropriate alternatives for normal flat-web girders in steel structures since they provide lighter and smaller beam features in steel design. Based on the existing literature, the corrugated web beams (CWBs) provide many advantages for structural applications. In this study, a series of numerical analyses have been performed in order to investigate the structural behaviour of steel I girders with corrugated web profile and to compare their mechanical performance with normal welded beams. Theory of Ultimate Limit State design has been adopted in accordance with AS4100 (Steel structures, Standard Australia, Sydney, 1998) along with considering geometric and material non-linearity in the numerical analyses in SAP2000. Comparing the results of the numerical investigation, merits of using corrugated welded beams (CWBs) over normal welded beams (WBs) have become apparent. Moreover, investigations regarding force–displacement relationship and buckling analysis of the webs were carried out and presented to further validate the advantages of using corrugated web beams. CWBs have been used in some parts of Australia without detailed information about their mechanical properties. Thus, based on the outcomes of this study, CWB table for dimensions and cross sectional properties has been developed and proposed for practical applications.

Steel I-section-plate girders with corrugated webs have been used worldwide as they provide more stability and light beam features in practical design. It is known from previous investigations that due to having numerous favourable properties, the corrugated-web beams have been used in different areas of structural engineering. Considering the raising popularity of using CWBs in steel design, some practical aspects of CWBs need to be investigated further, in which post-buckling strength is one of the most critical strengths that should be precisely estimated. To fulfill this requirement regarding the post-bucking strength determination for structural designers community, a numerical investigation has been conducted in this study to determine the moment capacity reduction factors for steel I girders with corrugated-web profile and to compare reduction factor values extracted from EN 1993-1-5 (Design of steel structures part 1–5: Plated structural elements, Eurocode 3, Brussels, 2006), AS4100 (Steel structures, Standard Australia, Sydney, 1998), and finite element analysis. Theory of Ultimate Limit State design has been adopted in accordance with AS4100 (1998) along with considering geometric and material non-linearity in the numerical analyses in SAP2000 software. Eventually, the results of the parametric study have been compared and discussed leading to presenting practical recommendations on the design of CWBs for bending strength.

This paper describes the reliability assessment of reinforced concrete columns designed according to the BS 81I0 (1997) ultimate limit state requirements. A typical cross-section (400 mm×400 mm) for three different commonly used columns was adopted and probabilistically assessed when all variables relating to the loading geometry and material properties are randomly distributed. First-Order Reliability Method (FORM) was employed to estimate the implied probability of failure for simulated loading and reinforcement quantities. The results showed that the cross-section (400 mm×400 mm) assessed could not sustain more than 40% of the expected ultimate design load before the violation of the limit state. In addition, the performance of reinforced concrete columns depends more on the applied load than on the amount of reinforcement used. The general inference from these results is that most of these types of columns designed according to BS 8110 (1997) have not failed, because they were carrying far less than their ultimate design loads.

In this work, the authors present the findings obtained from the analysis of calculating the bearing capacity of reinforced concrete elements under shear force. The chose element, a reinforced concrete beam, is designed according to Albanian Normative with two methods, rupture design method and limit state design method. Furthermore, is made a comparison between the analysis results. In the beginning a presentation is made with the theoretical solution of the problem and after that the comparison is based on numerical solution. The conclusions are followed from the recommendations given in the end of this work.

In the U.S., the current Load and Resistance Factor Design （LRFD） Specifications for highway bridges is a reliability-based formulation that considers failure probabilities of bridge components due to the actions of typical dead load and frequent vehicular loads. Various extreme load effects, such as earthquake and vessel collision, are on the same reliability-based platform. Since these extreme loads are time variables, combining them with not considered frequent. non- extreme loads is a significant challenge. The number of design limit state equations based on these failure probabilities can be unrealistically large and unnecessary from the view point of practical applications. Based on the opinion of AASHTO State Bridge Engineers, many load combinations are insignificant in their states. This paper describes the formulation of a criterion to include only the necessary load combinations to establish the design limit states. This criterion is established by examining the total failure probabilities for all possible time-invariant and time varying load combinations and breaking them down into partial terms. Then, important load combinations can be readily determined quantitatively,

The Italian “Guidelines for the seismic risk classification of constructions” approved in February 2017 define the technical principles for exploiting tax deductions with respect to seismic strengthening interventions on existing buildings (Sismabonus). Tax deductions represent a unique opportunity to improve the seismic safety of the existing Italian building stock. The guidelines are very simple and allow practitioners to deal with the sophisticated concepts behind modern seismic design, such as expected annual losses (EAL) and repair costs (expressed as a fraction of the Reconstruction Cost: %RC). The seismic risk classes of buildings and the class upgrade due to strengthening interventions can be assessed using the principles included in the guidelines. The seismic risk class is the minimum between the class defined by the building safety index at the ultimate limit state and the one related to the EAL. The latter class depends on the area under the curve of the expected losses, which is easily obtained by computing the safety index converted in the return period (annual frequency) at different limit states and the relevant %RC. This paper illustrates the technical principles at the base of the guidelines and the procedure used to calibrate the repair costs associated with the different limit states using the actual repair costs monitored in the reconstruction process following recent Italian earthquakes. Finally, simple tools to estimate the cost of the strengthening interventions to improve the seismic capacity at the life-safety limit states are provided.

This paper presents a novel descent algorithm based on the step-by-step iterative principle, applied to the optimum design of steel frames. The search consists on finding the direction which decreases the structural weight most quickly. As the design problem includes discrete variables, the optimum is found by evaluating the structural weight gradient step by step. The step size is controlled in such a way that convergence towards infeasible or suboptimal solutions is avoided. By properly choosing the initial solution, it is possible to increase the efficiency and the convergence speed of the algorithm. Many strategies, for the choice of initial design point, by making use of engineering intuitions or using optimized design obtained by other algorithms are discussed. Furthermore, it is confirmed in this study that the proposed algorithm can be used to improve optimum designs found by metaheuristic algorithms. The optimization results, relative to several weight minimizations problems of benchmark planar steel frames designed according to Load and Resistance Factor Design, American Institute of Steel Construction (LRFD-AISC) specifications, are compared to those obtained by different optimization methods. The comparison proves the efficiency and robustness as well as the prompt of convergence of the proposed descent algorithm developed in this paper.