Effect of skew on live load distribution in integral bridges

Erol, Mehmet Ali
Structural analysis of highway bridges using complicated 3-D FEMs to determine live load effects in bridge components is possible due to the readily available computational tools in design offices. However, building such complicated 3-D FEMs is tedious and time consuming. Accordingly, most design engineers prefer using simplified 2-D structural models of the bridge and live load distribution equations (LLDEs) available in current bridge design codes to determine live load effects in bridge components. Basically, the live load effect obtained from a 2-D model is multiplied by a factor obtained from the LLDE to calculate the actual live load effect in a 3-D structure. The LLDE available in current bridge design codes for jointed bridges were also used for the design of straight and skewed integral bridges by bridge engineers. As a result, these bridges are either designed conservatively leading to additional construction cost or unconservatively leading to unsafe bridge designs. Recently, LLDEs for integral bridges (IBs) with no skew are developed. To use these equations for skewed integral bridges (SIBs) a correction factor is needed to multiply these equations to include the effect of skew. Consequently, in this research study, skew correction factors for SIBs are developed. For this purpose, finite element models of 231 different three dimensional and corresponding two dimensional structural models of SIBs are built and analyzed under live load. The analyses results reveal that the effect of skew on the distribution of live load moment and shear is significant. It is also observed that skew generally tends to decrease live load effects in girders and substructure components of SIBs. Using the analyses results, analytical equations are developed via nonlinear regression techniques to include skew effects in the LLDEs developed for straight IBs. The developed skew correction factors are compared with FEAs results. This comparison revealed that the developed skew correction factors yield a reasonably good estimate of the reduction in live load effects due to the effect of skew.


Effect of AAC Infill Walls on Structural System Dynamics of a Concrete Building
Çelik, Ozan Cem (2016-01-01)
The effect of autoclaved aerated concrete (AAC) infill walls on the structural system dynamics of a two-story reinforced concrete building is investigated using its finite element structural model, which is calibrated to simulate the acceleration-frequency response curves from its forced vibration test. The model incorporating the AAC infill walls by equivalent diagonal struts captures the increase in lateral stiffness of the building and the torsional motions induced due to the asymmetrically placed AAC in...
A numerical procedure for the nonlinear analysis of reinforced concrete frames with infill walls
Güney, Murat Efe; Polat, Mustafa Uğur; Department of Civil Engineering (2005)
Materially non-linear analysis of reinforced concrete frame structures with infill walls requires appropriate mathematical models to be adopted for the beams and the columns as well as the infill walls. This study presents a mathematical model for frame elements based on a 3D Hermitian beam/column finite element and an equivalent strut model for the infill walls. The spread-of-plasticity approach is employed to model the material nonlinearity of the frame elements. The cross-section of the frame element is ...
The effect of group behavior on the pull-out capacity of soil nails in high plastic clay
Akış, Ebru; Bakır, Bahadır Sadık; Department of Civil Engineering (2009)
Soil nailing technique is widely used in stabilizing roadway and tunnel portal cut excavations. The key parameter in the design of soil nail systems is the pull-out capacity. The pull-out capacity of the soil nails can be estimated from the studies involving similar soil conditions or can be estimated from the empirical formulas. Field verification tests are performed before the construction stage in order to confirm the parameter chosen in the design of soil nailing system. It is reported in the literature...
Effect of out-of-plane behavior on seismic fragility of masonry buildings in Turkey
Ceran, Hasan Burak; Erberik, Murat Altuğ (Springer Science and Business Media LLC, 2013-10-01)
This study focuses on the evaluation of seismic safety of unreinforced masonry buildings in Turkey by using fragility curves generated for two behavior modes of load bearing walls: in-plane and out-of-plane. During generation of fragility curves, a force-based approach has been used. There exist two limit states in terms of base shear strength for in-plane behavior mode and flexural strength for out-of-plane behavior mode. To assess the seismic vulnerability of unreinforced masonry buildings in Turkey, frag...
Effect of soil-bridge interaction on the magnitude of internal forces in integral abutment bridge components due to live load effects
Dicleli, Murat (Elsevier BV, 2010-01-01)
In this study, the effect of soil-bridge interaction on the magnitude of the internal forces in integral abutment bridge (IAB) components due to live load effects is studied. For this purpose, structural models of typical IABs are built by including and excluding the effect of backfill and foundation soil. Analyses of the models are then conducted under an AASHTO live load. In the analyses, the effects of the backfill and foundation soil on the magnitude of the internal forces in IAB components are studied ...
Citation Formats
M. A. Erol, “Effect of skew on live load distribution in integral bridges,” M.S. - Master of Science, Middle East Technical University, 2009.