Performance of Girder Bridges under the Composite Action of Blast Loads and Earthquakes

2017 ◽  
Author(s):  
Jingyu Wang ◽  
Wancheng Yuan ◽  
Fengming Wang
Keyword(s):  
Blast Loads ◽  
Composite Action ◽  
Girder Bridges

Composite Steel Stud Blast Panel Design and Experimental Testing

2011 ◽  
Vol 82 ◽  
pp. 479-484
Author(s):  
Thomas J. Mander ◽  
Zachery I. Smith
Keyword(s):  
Shock Tube ◽  
Experimental Testing ◽  
Blast Resistance ◽  
Wire Mesh ◽  
Blast Loads ◽  
Fiber Reinforced ◽  
Composite Action ◽  
Concrete Layer ◽  
Steel Stud ◽  
Composite Steel

Based on Federal Aviation Authority (FAA) requirements, project specific blast loads are determined for the design of a new airport traffic control tower. These blast loads must be resisted by exterior wall panels on the control tower, protecting building occupants from intentional explosives attack scenarios. Such blast resistant walls are typically constructed of thick reinforced concrete panels or composite steel plate and rolled sections, as conventional building cladding systems have relatively low blast resistance. While these more robust design approaches are valid, the additional cladding mass they represent will significantly increase the base shear and overturning demand in seismic zones. This paper investigates the use of a light structural system comprised of a steel stud wall assembly partially embedded in a thin layer of concrete to obtain composite action. Fiber reinforced polymer (FRP) composites are also included to increase the blast resistance and aid in keeping the panel weight to a minimum. Two full-scale composite steel stud walls are designed, constructed, and tested dynamically in the BakerRisk shock tube. The stud walls consist of back-to-back 150 mm deep, 14 gauge (1.8 mm thick), cold-formed steel studs spaced at 610 mm on center. Both specimens have a 50 mm thick normal weight concrete layer, reinforced with welded wire mesh that is welded to the stud compression flanges to achieve composite action. Two layers of Tyfo® SEH-51A fiber reinforced composites are used on the tension flange of the steel studs. A single layer of Tyfo® SEH-51A composites is used on the tension face of the concrete layer between the studs for one of the specimens. Web stiffeners are used at the bearing support to prevent premature web crippling shear failure of the specimens. The stud walls are analyzed using single-degree-of-freedom (SDOF) models. A non-linear moment-curvature relationship, accounting for actual material constitutive properties, is used for determining the resistance function of the walls. Blast pressure and impulse data from the shock tube tests is used to compare analytical predictions to the measured displacement-time response. Analytical predictions of panel response for both tests are within ten percent of the observed response based on displacement.

Strengthening of steel girder bridges using coiled pins

2019 ◽  
Author(s):  
Magnús Arason ◽  
Guðmundur Ragnarsson ◽  
Peter Collin ◽  
Robert Hällmark
Keyword(s):  
Bearing Capacity ◽  
Concrete Slab ◽  
Bottom Flange ◽  
Steel Girders ◽  
Steel Girder ◽  
Composite Action ◽  
Shear Connection ◽  
Girder Bridges ◽  
Steel Girder Bridges ◽  
Composite Bridges

<p>A requirement for heavier vehicular transport on the Norwegian road network has resulted in a demand for increased bearing capacity for many of the older bridges in the country. Many of the bridges that have been found to have insufficient capacity against present-day demands are steel girder bridges with concrete slabs without a shear connection between steel and concrete. There is a large number of bridges of this type in Norway and the paper presents strengthening of two of those, in Aust-Agder county in the south of the country. These bridges are approximately 30 m long, single span. The bearing capacity has been upgraded by installing composite action between the steel girders and the concrete slab using coiled pins, in conjunction with thickening of the bottom flange of the steel girders. To obtain composite action, the pins are fitted to tightly drilled holes through the top flange of girders up into the concrete slab. Coiled pins have not been used much for bridge applications. In the work presented, the method has been found to have advantages in terms of cost and workability. Furthermore, the method has benefits when viewed from an environmental standpoint, since it allows strengthening of existing non-composite bridges using relatively little new material, and minimizes traffic disruptions.</p>

Long-term study on the effect of temperature on composite action and variation of neutral axis in slab on girder bridges

2019 ◽  
Vol 19 (5) ◽  
pp. 1577-1589
Author(s):  
B Algohi ◽  
D Svecova ◽  
A Mufti ◽  
B Bakht ◽  
D Thomson
Keyword(s):  
Concrete Slab ◽  
Neutral Axis ◽  
Effect Of Temperature ◽  
Steel Girders ◽  
Cold Temperatures ◽  
Mechanical Feature ◽  
Composite Action ◽  
Girder Bridges ◽  
Long Term Study ◽  
Over Time

Composite action between steel girders and concrete slab is an important mechanical feature that needs to be maintained so that bridges can carry the applied load safely. This mechanical feature is maintained through the shear studs installed at the top flange of the steel girders. These shear studs keep the steel girders and the concrete slab working as one unit, resulting in a stronger section than if each element works separately. The composite action can be investigated using several methods of which one is the study of the position of the neutral axis (NA). The variation of the position of the NA over time gives an indication about the structural performance of the composite section. In this study, the variation of the position of the NA over time is investigated. Two bridges located in Manitoba were investigated in this study. The variation of the NA is observed as a result of variation of ambient temperature (temperature). Regression models are suggested to relate variation of the NA to the temperature that was measured beside the web of one of the bridge girders. Repeatability analysis over 4 years was conducted, confirming that the NA varies cyclically over years. It is suggested that this variation indicates that there is a change in the degree of composite action assuming that cold temperatures will induce more connection between the steel girders and the concrete slab as a result of thermal contraction of the shear studs. In addition, the stiffness of the material could be affected due to change of temperature. The other possibility is that an axial force develops in the beam as a result of the bearing restraint during the passing of vehicles on the bridge. The results found in this study will eventually lead to enhancements of the design procedures that currently assume a fixed position of the NA over time of composite sections of bridges, similar to the bridges presented in this study.

Parametric study on noncomposite slab-on-girder bridges with enforced frictional contact

1994 ◽  
Vol 21 (2) ◽  
pp. 237-250 ◽  
Author(s):  
Jian Jun Lin ◽  
Denis Beaulieu ◽  
Mario Fafard
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Parametric Study ◽  
The Finite Element Method ◽  
Steel Girders ◽  
Steel Girder ◽  
Composite Action ◽  
Girder Bridges ◽  
Bridge Models ◽  
Element Method

Using post-tensioned steel rods for strengthening noncomposite slab-on-steel girder bridges has the beneficial effects of both stabilizing the steel girders laterally and developing partial composite action longitudinally. The stabilizing effect and development of partial composite action are achieved by taking advantage of friction developed at the steel–concrete interface. A bridge reinforced by this technique is expected to have a higher load-carrying capacity and better load distribution under heavy traffic loads. Prestressed rods have been successfully used to strengthen 1/3 scale noncomposite bridge models in laboratory.The concrete slab-on-steel girder bridge models reinforced by prestressed rods are analyzed numerically in this paper by the use of the finite element method. Corresponding noncomposite models are also simulated for comparison to investigate the efficiency of this strengthening technique. The effects of variables such as the number of rods, prestressing level, type of load, slab thickness, steel girder slenderness, girder spacing, and ratio of radii of gyration of steel girders on the strengthening efficiency are studied by the finite element method. A full-scale bridge is analyzed to demonstrate the effect of the proposed reinforcing technique. Key words: bridge, composite action, contact, finite element, friction, parametric study, strengthening.

Study on Finite Element Modeling of Girder Bridges

2013 ◽  
Vol 671-674 ◽  
pp. 1051-1054
Author(s):  
Xiao Hui Xia
Keyword(s):  
Finite Element ◽  
Finite Element Modeling ◽  
Beam Element ◽  
Physical Behavior ◽  
Composite Action ◽  
Element Modeling ◽  
Eccentricity Effect ◽  
Girder Bridges ◽  
Modeling Techniques ◽  
Node Location

The modeling techniques selected for girder bridges should be capable of including physical behavior, such as composite action and the eccentricity effect between the slab deck and the girder. In this paper, we find that the ANSYS has the capability of offsetting the beam element from a reference node location in order to define the centric location of the section relative to the node location.

Delayed development of composite action in steel girder bridges

2006 ◽  
Vol 2 (3) ◽  
pp. 119-132
Author(s):  
Atorod Azizinamini ◽  
Aaron J. Yakel
Keyword(s):  
Steel Girder ◽  
Composite Action ◽  
Girder Bridges ◽  
Steel Girder Bridges ◽  
Delayed Development
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