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Fu G.,Wayne State University | Fu G.,Tongji University | Feng J.,WSP Cantor Seinuk | Dekelbab W.,Transportation Research Board
Practice Periodical on Structural Design and Construction | Year: 2010

Commercial vehicle weight limits here refer to those on the gross weight, axle spacing, and axle weights. They have a notable influence on the deterioration and lifespan of highway facilities such as pavements and bridges. A new methodology is presented here for estimating the monetary impact to a network of highway bridges due to commercial vehicle weight limit increase. This methodology focuses on four categories of cost impact: (1) life reduction due to fatigue of steel components; (2) life reduction due to fatigue of reinforced concrete decks; (3) requirements for addressing deficiency of existing bridges; and (4) capacity requirements for new bridges. For illustration, an application example of the new methodology is presented. The results show that Categories 3 and 4, additional inadequate bridges and increased requirements for new bridges, contribute more significantly to the total impact cost. In addition, a computer software program for the methodology has been developed and is introduced in this paper to facilitate implementation. It is intended to be used for highway planning at different network levels, such as for state, provincial, federal, or national jurisdictions. © 2010 ASCE. Source


Fu G.,Wayne State University | Fu G.,Tongji University | Fu G.,Fuzhou University | Zhuang Y.,Wayne State University | Feng J.,WSP Cantor Seinuk
Journal of Bridge Engineering | Year: 2011

This paper focuses on the behavior of skewed concrete bridge decks on steel superstructure subjected to truck wheel loads. It was initiated to meet the need for investigating the role of truck loads in observed skewed deck cracking, which may interest bridge owners and engineers. Finite-element analysis was performed for typical skewed concrete decks, verified using insitu deck strain measurement during load testing of a bridge skewed at 49.1. The analysis results show that service truck loads induce low strains/stresses in the decks, unlikely to initiate concrete cracking alone. Nevertheless, repeated truck wheel load application may cause cracks to become wider, longer, and more visible. The local effect of wheel load significantly contributes to the total strain/stress response, and the global effect may be negligible or significant, depending on the location. The current design approach estimates the local effect but ignores the global effect. It therefore does not model the situation satisfactorily. In addition, total strain/stress effects due to truck load increase slightly because of skew angle. © 2011 American Society of Civil Engineers. Source


Fu G.,Wayne State University | Fu G.,Tongji University | Feng J.,WSP Cantor Seinuk | Dimaria J.,Wayne State University | Zhuang Y.,Wayne State University
Bridge Maintenance, Safety, Management and Life-Cycle Optimization - Proceedings of the 5th International Conference on Bridge Maintenance, Safety and Management | Year: 2010

Many highway bridge decks are made of reinforced concrete for a number of advantages. On the other hand, concrete materials are susceptible to cracking, which may expedite deterioration. This paper focuses on the behavior of skewed concrete bridge decks on steel superstructure subjected to thermal load and truck load. It was to meet the need of the Michigan Department of Transportation for investigating observed skewed deck cracking. Full scale bridge deck measurement and finite element analysis were performed. The numerical modeling was verified using the in-situ deck strain measurement of the bridge skewed at 49.1°. The results show that service truck loads induce low strains / stresses in the deck, unlikely to initiate concrete cracking alone. Rather the thermal load and shrinkage of cement caused the observed cracking, due to the constraint of the supporting beams. Nevertheless, repeated truck load application may cause the cracks to become wider, longer, and more visible. In addition, the skew angle increases, not very significantly, the total strain/stress effect due to the truck wheel load. © 2010 Taylor & Francis Group, London. Source


Fu G.,Wayne State University | Fu G.,Tongji University | Feng J.,WSP Cantor Seinuk | Dimaria J.,WSP Cantor Seinuk | Zhuang Y.,Wayne State University
Bridge Maintenance, Safety, Management and Life-Cycle Optimization - Proceedings of the 5th International Conference on Bridge Maintenance, Safety and Management | Year: 2010

Many highway bridge decks are made of reinforced concrete for a number of advantages. On the other hand, concrete materials are susceptible to cracking, which may expedite deterioration. This paper focuses on the behavior of skewed concrete bridge decks on steel superstructure subjected to thermal load and truck load. It was to meet the need of the Michigan Department of Transportation for investigating observed skewed deck cracking. Full scale bridge deck measurement and finite element analysis were performed. The numerical modeling was verified using the in-situ deck strain measurement of the bridge skewed at 49.1°. The results show that service truck loads induce low strains / stresses in the deck, unlikely to initiate concrete cracking alone. Rather the thermal load and shrinkage of cement caused the observed cracking, due to the constraint of the supporting beams. Nevertheless, repeated truck load application may cause the cracks to become wider, longer, and more visible. In addition, the skew angle increases, not very significantly, the total strain/stress effect due to the truck wheel load. © 2010 Taylor & Francis Group, London. Source


Fernandez Ruiz M.,Ecole Polytechnique Federale de Lausanne | Mirzaei Y.,WSP Cantor Seinuk | Muttoni A.,Structural Concrete Laboratory at EPFL
ACI Structural Journal | Year: 2013

Reinforced concrete flat slabs are a common structural system for cast-in-place concrete slabs. Failures in punching shear near the column regions are typically governing at ultimate. In case no punching shear or integrity reinforcement is placed, failures in punching develop normally in a brittle manner with almost no warning signs. Furthermore, the residual strength after punching is, in general, significantly lower than the punching load. Thus, punching of a single column of a flat slab overloads adjacent columns and can potentially lead to their failure on punching, thus triggering the progressive collapse of the structure. Over the past decades, several collapses have been reported due to punching shear failures, resulting in human casualties and extensive damage. Other than placing conventional punching shear reinforcement, the deformation capacity and residual strength after punching can also be enhanced by placing integrity reinforcement to avoid progressive collapses of flat slabs. This paper presents the main results of an extensive experimental campaign performed at the Ecole Polytechnique Fédérale de Lausanne (EPFL) on the role of integrity reinforcement by means of 20 slabs with dimensions of 1500 x 1500 x 125 mm (?5 ft x 5 ft x 5 in.) and various integrity reinforcement layouts. The performance and robustness of the various solutions is investigated to obtain physical explanations and a consistent design model for the load-carrying mechanisms and strength after punching failures. Source

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