Search results for "CONCRETE STRUCTURES"

Simultaneous measurement of temperature and strain in glass fiber/epoxy composites by embedded fiber optic sensors: II. Post-cure testing

2007

In this paper the use of fiber optic sensors embedded into GFRP laminates for structural health monitoring of thermo-mechanical loads is presented. The proposed sensing system, consisting of two coupled fiber Bragg grating (FBG) sensors, allows the simultaneous measurement of both temperature and strain by decoupling the change in reflected wavelength induced by temperature variations from that induced by either mechanical or apparent strain, with significant advantages either for monitoring the composite cure kinetics, as described in the accompanying paper (Part I), or for assessing the structural response to thermo-mechanical loads. Both thermal ramp and mechanical static/dynamic bending…

Increasing the Capacity of Existing Bridges by Using Unbonded Prestressing Technology: A Case Study

2014

External posttensioning or unbonded prestressing was found to be a powerful tool for retrofitting and for increasing the life extension of existing structures. Since the 1950s, this technique of reinforcement was applied with success to bridge structures in many countries, and was found to provide an efficient and economic solution for a wide range of bridge types and conditions. Unbonded prestressing is defined as a system in which the post-tensioning tendons or bars are located outside the concrete cross-section and the prestressing forces are transmitted to the girder through the end anchorages, deviators, or saddles. In response to the demand for a faster and more efficient transportati…

Incremental dynamic based fragility assessment of reinforced concrete structures: Stationary vs. non-stationary artificial ground motions

2017

Abstract Artificial and natural records are commonly employed by researches and practitioners to perform refined seismic assessments of structures. The techniques for the generation of artificial records and their effectiveness in producing signals which are significantly representative of real earthquakes are still debated as well as results of the consequent seismic assessment to expect from their application. The paper presents an in-depth comparative study highlighting the effect of employing different typologies of artificial ground motion records on seismic assessment results, especially addressing seismic fragility curves. Three sets of 50 stationary, nonstationary evenly modulated a…

Il recupero parziale di opere in muratura di interesse storico in zona sismica

2011

Structural assessment of a reinforced concrete water tower

2019

The paper presents a structural appraisal of a reinforced concrete water tower at the Public Abattoir in Malta. The water tower was constructed in the first half of the 20th century and consists in a reinforced concrete thin shell structure supported on twelve columns. Detailed drawings and a refined 3D model were prepared based on detailed site measurements of the structure. The concrete was assessed through non-destructive tests and with reference to extracted concrete core samples from different parts of the structure and extracted steel reinforcement samples. Detailed deterioration mapping was conducted for the entire structure. This data was used to model the structure and analyse it t…

Nonlinear Response of RC Structures: Statistical Effects of Artificial Ground Motions

2020

The selection of seismic inputs for nonlinear dynamic analysis is widely debated, mainly focusing on the advantages and disadvantages provided by the choice of natural, simulated or artificial records. However, most of the available technical codes do not provide always the same suggestions and well-defined procedures for the generation of artificial ground motions. Considering that the strategy of the generation of accelerograms makes some doubts raise about the possible effect on the structural response, the work aims to investigate on the differences of the structural behavior by using accelerograms nominally equivalent but different in terms of stationarity. This paper presents a compar…