The recent progress of recycled steel fiber reinforced concrete

A review of mechanical properties of fibre reinforced concrete at elevated temperatures

Bridges are critical infrastructure, and effective operation and maintenance (O&M) is essential for ensuring the good condition of bridges. Owing to the increasing complexity of modern bridges and ...

Critical review of data-driven decision-making in bridge operation and maintenance

Experimental and numerical investigations on performance of reinforced concrete slabs under explosive-induced air-blast loading: A state-of-the-art review

Mechanical behaviour of ultra-high strength concrete at elevated temperatures and fire resistance of ultra-high strength concrete filled steel tubes

Recent trends in ultra-high performance concrete (UHPC): Current status, challenges, and future prospects

Fire resistance of geopolymer concrete: A critical review

Large-span prestressed concrete (PC) box-girder bridges suffer excessive vertical deflections and cracking. Recent serviceability failures in China show that the current Chinese standard modeling approach fails to accurately predict long-term deformations of large box-girder bridges. This hinders the efforts of inspectors to conduct satisfactory structural assessments and make decisions on potential repair and strengthening. This study presents a model-updating approach that aims to assess the models used in the current Chinese standard and improve the accuracy of numerical modeling of the long-term behavior of box-girder bridges, calibrated against data obtained from a bridge in service. A three-dimensional finite-element model representing the long-term behavior of box-girder sections is initially established. Parametric studies are then conducted to determine the relevant influencing parameters and to quantify the relationships between those and the behavior of box-girder bridges. Genetic algorithm optimization, based on the response-surface method (RSM), is used to determine realistic creep and shrinkage levels and prestress losses. The modeling results correspond well with the measured historic deflections and the observed cracks. This approach can lead to more accurate bridge assessments, which result in safer strengthening and more economic maintenance plans.

/pdf/modeling-for-assessment-of-long-term-behavior-of-prestressed-4pdxu32w74.pdf

Modeling for assessment of long-term behavior of prestressed concrete box-girder bridges

Connections are critical structural elements of building frames, and in a fire are subject to forces very different from those at the ambient temperature for which they are designed. The fracture of a connection can cause the collapse of the connected beam, which may lead to a progressive collapse sequence affecting the entire building. This paper overviews the sequence of research on connection behaviour in a fire at the University of Sheffield. Early work focused on studying connections in terms of their moment–rotation behaviour alone. Concurrent full-scale building fire tests led to the realization that the tying capacity of connections is of prime importance for maintaining the structural stability in a fire. For whole-structure numerical modelling in performance-based fire engineering design, the development of the component-based approach, which was initially introduced for ambient temperature connection design, is an appropriate way to rationalize and model connection behaviour under these complex loadings. The effect of high co-existent rotation on the tying capacity of connections has been studied in furnace tests at various temperatures, which have provided data to assist in the characterization of the component-based model. A general component-based connection element, into which appropriate component models can be inserted, has been developed so that full connection performance, including fracture of components, can be integrated into global non-linear structural fire analysis. This will allow buildings to be modelled for a range of fire scenarios so that they can be designed to avoid progressive collapse in a fire.

Shan-Shan Huang

Papers

Recent trends in ultra-high performance concrete (UHPC): Current status, challenges, and future prospects

Fire resistance of geopolymer concrete: A critical review

Modeling for assessment of long-term behavior of prestressed concrete box-girder bridges

The role of connections in the response of steel frames to fire

Fire spalling behavior of high-strength concrete: A critical review