Influence of the Weld Joint Position on the Mechanical Stress Concentration in the Construction of the Alternative Skid Car System’s Skid Chassis

This paper deals with the optimization of the crossbars, parts of the existing frame of the experimental system of the Alternative SkidCar. This part plays a crucial role and is designed to enable and ensure reduced adhesion conditions between the vehicle and the road. To this end, its optimization targeted here is performed using both analytical calculations and simulations in MSC Adams software, wherein the loading forces and boundary conditions on the frame support wheels are obtained considering the static conditions, as well as the change of the direction of travel. The least favourable load observed was used, later on, as the input value for the strength analysis of the frame. The analysis was performed using the finite element method (FEM) in SolidWorks. Based on the linear and nonlinear analyses performed, the course of stress on the frame arms and critical points with the highest stress concentration were determined. Subsequently, according to the results obtained, a new design for the current frame was proposed and, thereby, warrants greater rigidity, stability and strength to the entire structure, while reducing its weight and maximizing the potential of the selected material. The benefit of the current contribution lies in the optimization of the current frame shape, in terms of the position of weld joints, the location of the reinforcements and the thickness of the material used.

Timber Based Integrated Techniques to Improve Energy Efficiency and Seismic Behaviour of Existing Masonry Buildings

The retrofit solutions studied herein aim to improve the seismic and energetic behaviours of existing masonry buildings to guarantee safety and the preservation of the building heritage. The retrofit consists of timber-based products (panels and strong-backs) fixed to the masonry walls using mechanical point-to-point connections; the durability and the hygrothermal performance of the solutions are guaranteed by insulation layers and membranes. The thermophysical properties of the retrofitted walls were evaluated by means of analytical and numerical analyses, considering the heat transmission in both steady and unsteady state conditions and the thermal bridge in correspondence with the corner of the wall. The in-plane seismic behaviour of the retrofitted walls was numerically investigated through nonlinear analyses. The influence of various parameters (such as masonry and insulation properties) on the performance of the retrofit solutions was analysed via parametric simulations.

Precast Dapped End - Nonlinear Analysis

The article follows the results from the experiments published at the conferences Concrete days 2014 [1] and 2016 [2], in the paper [3], and also in the magazine Beton TKS [4]. The goal of the experiment was the verification of dapped ends with the different configuration of the hanger stirrups. Subsequently, the nonlinear analyses were performed in the scientific program ATENA. In this article, a new comparison with calculations using the CSFM (Compatible Stress Field Method), implemented in software IDEA StatiCa Detail, is performed

Dynamic seismic analysis of bridge using response spectrum and time history method

Dynamic analysis is very important to better understand the performance of structural elements of a bridge. For this purpose, a seismic analysis of an Algerian highway bridge designed with the new Algerian seismic bridge regulation (RPOA -2008) was carried out using linear and nonlinear analyses. Therefore, response spectrum, time history analyses were performed to evaluate the seismic responses of the designed bridge. The performance of the designed bridge is assessed using 10 ground motion records. The proposed methodology allows an efficient comparison of the seismic response of the bridge in terms of base shear forces, bending moment and displacements. Finally, the paper concludes with a discussion of the specific outcomes.

Numerical Evaluation of Prequalified End-Plate Connections Used in a Framed Steel Industrial Structure

The design of end-plate connections for steel structures is more loosely specified in Chilean regulations than in American regulations. Nevertheless, eight-bolt extended stiffened (8ES) end-plate connections have not derived benefit from extensive past research, and therefore, their normative recommendations are quite constraining. In this study, both the prequalification and qualification limits are evaluated, and the linear and nonlinear analyses of a connection from a case study focused on a typical industrial structure, characterized by its reduced dimensions, are carried out. For the design of the connection, a spreadsheet was developed based on AISC 358. The nonlinear analysis was modeled using the finite element method, and it is confirmed that the normative recommendations restrict the design in a very conservative way, resulting in oversizing. Finally, a new optimized connection configuration is proposed and analyzed without stiffeners.

Repair project of a vehicular bridge damaged during the 2017 Puebla- Morelos earthquake: seismic evaluation

<p>This paper shows the results of nonlinear analyses, static and dynamic, conducted on a vehicular bridge located in Mexico City. The main characteristics of the developed numerical model and the results of the analysis, in terms of capacity curves, global and by element, are presented. Two repair cases were studied. The first one considers seismic restrainers, located at the bridge abutments, which can effectively limit the lateral movements. The second case considers reduced lateral restriction. The results show that the former case provides an adequate safety factor for the bridge, while the latter resulted in a marginal safety factor.</p>