Evaluation of Iterative DBD Procedures for Bridges

This report addresses the problem of the Displacement Based Evaluation/Design (DBE/D) of reinforced concrete bridges. Throughout the report, the aims and limitations of current seismic evaluation and design practice and the tendencies of the displacement-based seismic evaluation/design are discussed. It presents a state-of-the-art review on the most important results and lessons derived from previous works, and based on them, two evaluation/design methods consistent with the performance-based seismic design philosophy are presentedJRC.G.5-European laboratory for structural assessmen

Validation of Simplified Procedures for Predicting Global Response in the Context of DBD of Bridges, Including the Flexibility of Foundations / Case Study Comparison of DBD Iterative Procedures for Bridges

The present report collects the work performed in Deliverable 112 "Validation of simplified procedures for predicting global response in the context of DBD of bridges, including the flexibility of foundations" and in the chapter corresponding to Displacement Based Design of Deliverable 113 "Case study comparison of DBD iterative procedures for bridges" of the LESSLOSS Project, dealing with three main subjects: verifying that the concept of the Substitute Structure constitutes a valid means of predicting the response of a bridge structure undergoing plastic deformations; formulating a procedure for the displacement based design performance of bridges; defining the parameters of a Takeda Model to be used within the context of non-linear time history analysis of bridges with RC rectangular hollow columns.JRC.G.5-European laboratory for structural assessmen

Simplified Models/Procedures for Estimation of Secant-to-Yielding Stiffness, Equivalent Damping, Ultimate Deformations and Shear Capacity of Bridge Piers on the Basis of Numerical Analysis

The present report gives charts and expressions for computing the equivalent stiffness and damping of bridge piers of rectangular hollow cross section at maximum displacement within the framework of displacement based design and assessment of bridges, based on the results of parametric non-linear cyclic fibre section analysis calibrated from full-scale experimental results. A state of the art review is presented concerning the different approaches that may be adopted to model shear effects in reinforced concrete columns concerning the different approaches that may be adopted to model the shear effects in reinforced concrete columns.JRC.G.5-European laboratory for structural assessmen

Composite Solutions for Construction Sector

FRP composite materials have been successfully used for several decades in the aerospace industry, while their use in Civil Engineering is relatively recent and generally in the form of sheets and strips employed to strengthen existing reinforced concrete structures. Since the construction of the first all‐FRP‐composite bridge in 1982, in Miyun, China, FRP composites have been gradually gaining acceptance as a new construction material for bridges and footbridges with some notable applications in Spain. Their use offers a number of advantages with respect to traditional materials:Since FRP composite members are lighter than those built using concrete and steel, they need less powerful equipment for their transport and installation;Their lightweight fosters prefabrication, speeding up construction processes, thus helping in the reduction of the impact of worksites on their surrounding areas;FRP composites can curb maintenance cost of infrastructures since they do not suffer from galvanic corrosion

Composite materials applied in infraestractures: recycling strategies

Conferència a càrrec de Carlo Paulotto, d'ACCIONA (Madrid, Spain) sobre la utilització de materials compòsits en infraestructures, les aplicacions que s'hi poden fer i les diferents estratègies de recliclatg

Delay correlation of mechanical hysteresis and damping

This paper presents a procedure for calculating the effective equivalent structural properties (stiffness and damping) of hysteretic systems from the time histories of their dynamic response. The method is based on the finding that the effective dynamic damping is proportional to the product of the structural natural frequency and the delay between the overall restoring force and the structural displacement. The delay is calculated from the time-shifted cross-correlation between the structural force and displacement; and the same procedure also allows us to compute the instantaneous period of the response. Having calculated the delay and the period of forced oscillation, it is shown how, by computing the standard deviations of the force-displacement signals, it is possible to compute both the equivalent damping and the linearised stiffness. By implementing this procedure sequentially through moving windows, it is possible to monitor the non-linear evolution in time. Some proofs are given for some easily tractable mathematical cases such as for linear simple harmonic and seismic responses, conjecturing that the method can be equally applied for transient forcing functions of non-linear systemsJRC.G.5-European laboratory for structural assessmen

Wind tunnel evaluation of mean wind pressure on a frame-type signboard

In the context of the growing concern for the wind effects and the wind design of "street architecture" (bill-boards, traffic signs, traffic lights, etc.), wind tunnel tests have been carried out on a model of a frame-type signboard, placed within a regular array of buildings. The first experimental results, reported here, help to clarify the relationship between the wind loading on the signboard and the characteristics of the wind acting on the surrounding buildings. (c) 2006 Elsevier Ltd. All rights reserved

Hollow bridge-pier properties for response spectrum analysis

The present paper proposes equivalent stiffness and energy dissipation properties of reinforced concrete hollow bridge piers to be used in the context of response spectrum performance based assessment and design. The work is carried out by performing parametric numerical analysis using a 2D fibre model calibrated against experimental results and by varying the longitudinal steel reinforcement ratio, height over width ratio, normalised axial force, level of confinement and concrete class of a rectangular hollow section reinforced with Tempcore B500C steel. The results of the analysis are given in the form of charts and closed form expressions for the yield curvature and moment, ultimate ductility, post yielding stiffness ratio and energy dissipated of the section, and are translated to the member level through the plastic hinge length approach. Likewise, the parameters of a Takeda model derived from the parametric analysis are given for use in nonlinear time history analysis.JRC.G.5-European laboratory for structural assessmen

Displacement Based Design Procedures for RC Bridges - Formulation and Comparison of Two Approaches

This paper presents the formulation, evaluation and comparison of two newly developed displacement based design procedures for reinforced concrete bridges. The foundations of both methods are established within the framework of the performance based design philosophy, however they are different inasmuch as the first one is an iterative linear method based on the concepts of the substitute structure, proposed more than three decades ago, and the use of seismic demands given by damping reduced design spectra and the other is a direct non-iterative non-linear procedure based on the concepts of a non-linear SDOF reference system and seismic demands given by uniform hazard design spectra for an assumed rate of exceedence of the target performance. To understand the potential of application of both methods, the issue of bridge regularity is explicitly examined showing that, further to the concept that regularity of a bridge is closely related to the expected seismic performance under design actions, it is also linked to the used performance based evaluation/design method. It is shown that when a bridge structure is irregular, both proposed procedures may lead to incorrect evaluations/designs unless some additional considerations are introduced in the procedures. The results obtained from both methods are illustrated by applying them to five bridges.JRC.G.5-European laboratory for structural assessmen