Numerical analysis and assessment of a cable-stayed bridge during construction

• Type: Article in International Conference Proceedings Book
• Date: 2006

Authors

António Abel Henriques (Author) FEUP; Rui Faria (Author) FEUP; Joaquim Figueiras (Author) FEUP; Felix, CM (Author) Other

Conference proceedings International

Title: Proceedings of the 3rd International Conference on Bridge Maintenance, Safety and Management - Bridge Maintenance, Safety, Management, Life-Cycle Performance and Cost

Pages: 813-814

3rd International Conference on Bridge Maintenance, Safety and Management - Bridge Maintenance, Safety, Management, Life-Cycle Performance and Cost

Porto, 16 July 2006 through 19 July 2006

Indexing

Scopus - 1 Citation

COMPENDEX

Scientific classification

FOS: Engineering and technology > Civil engineering

CORDIS: Technological sciences > Engineering > Civil engineering > Structural engineering

Other information

Authenticus ID: P-007-P1C

Abstract (EN): Monitoring of bridges can provide many benefits to designers, constructors and operators. They are important to build more durable and safer structures. LABEST research unit has been developing and applying this new area of knowledge to different structural systems and real structures, answering to construction companies needs and contributing to cheaper and safer structures that can be built and operated for long periods of time with minimum maintenance. Interpretation and discussion of the results obtained during a monitoring campaign of a structural system is a difficult task. Numerical models are important tools to improve the application of monitoring systems. They can be used to define adequate algorithms for structural damage detection and to assess accuracy and confidence on results achieved from monitoring. This work presents an evaluation of the accuracy obtained from the new monitoring system set developed at LABEST research unit applied to a cable-stayed bridge built in the city of Oporto (Fig. 1) and designed by GRID - Consultas, Estudos e Projectos de Engenharia, Lda. Results will be presented and discussed by comparing the values from the monitoring campaign with the ones from a numerical analysis. Strains, temperatures, rotations and deflections have been monitored on the bridge deck and on the mast during construction, as well as during the subsequent loading test and current service-life by using a standard system based on electrical sensors providing the automatic and simultaneous interrogation of all sensors, with a minimum human intervention (Félix, 2005). A numerical analysis of the construction was also performed. The inherent numerical program was developed at LABEST, and it is based on finite element techniques using an elasto-visco plastic formulation (Henriques, 1998). The effects due to quasi instantaneous loads applied during the construction phases, such as, application of prestress or deck concreting are emphasized. Thermal effects due to variations of (Figure Presented) temperature and time dependent phenomena will be discussed taking into account the information obtained from the monitoring campaign. The monitoring during construction included the instrumentation of five sections at the deck and two sections at the mast (Fig. 2). For the observation of these sections, thirty eight electric strain gages and eleven temperature sensors were embedded into concrete. The equipment is programmable with a predefined time interval between acquisitions; its use is autonomous, allowing the monitoring of the structural behavior for several weeks. The constructive process was simulated by a finite element code that accounts for the non-linear constitutive relationships of concrete and steel, as well as time-dependent effects like concrete ageing, shrinkage and creep and prestress relaxation (Henriques, 1998; Henriques & Figueiras, 2002). The segmental erection of the bridge was simulated by a discretization with Timoshenko beam finite elements for the reinforced concrete, and axial curvilinear elements for the prestressed cables. Results obtained from monitoring and numerical analysis were compared, some differences were observed. They can be explained by simplifications introduced in the numerical model, such as the necessity to simulate cast-in-place of girder segments or prestressing operations by instantaneous loads; or by uncertainties concerning the real concrete modulus of elasticity and the prestress actually applied. Despite these differences, results show identical variations and values are similar. © 2006 Taylor & Francis Group.

Language: English

Type (Professor's evaluation): Scientific

No. of pages: 2