Lateral Load Distribution Factors for Military Vehicles on Multi-girder Bridges
Author : Juan C. Piñero
Publisher :
Page : 129 pages
File Size : 33,78 MB
Release : 2002
Category : Bridges
ISBN :
A Model Study of Lateral Load Distribution on Multi-girder Single Span Bridges
Author : Oswaldo Enrique Palacio Bustillo
Publisher :
Page : 452 pages
File Size : 17,23 MB
Release : 1968
Category : Concrete bridges
ISBN :
Book Description
Live Load Distribution in Multi-cell Box Girder Bridges and Its Comparison with the AASHTO LRFD Bridge Design Specifications
Author : Shin-Tai Song
Publisher :
Page : 546 pages
File Size : 39,52 MB
Release : 2001
Category : Box girder bridges
ISBN :
Book Description
Challenges, Opportunities and Solutions in Structural Engineering and Construction
Author : Nader Ghafoori
Publisher : CRC Press
Page : 1890 pages
File Size : 24,9 MB
Release : 2009-10-29
Category : Technology & Engineering
ISBN : 1439859434
Book Description
Challenges, Opportunities and Solutions in Structural Engineering and Construction addresses the latest developments in innovative and integrative technologies and solutions in structural engineering and construction, including: Concrete, masonry, steel and composite structures; Dynamic impact and earthquake engineering; Bridges and
Influence of Load Reduction in Multi-lane Bridges
Author : Imad Youssef Naddaf
Publisher :
Page : 296 pages
File Size : 31,97 MB
Release : 1998
Category :
ISBN :
Book Description
This thesis investigates the behavior of multi-lane steel girder bridues subject to reduced loading using the finite element method The most critical behavior of a highway bridge is thought to result from a fully loaded bridge (live load on all lanes) It is a common practice to apply reduction factors for bridges with more than two lanes These reduction factors are to account for the probability that all lanes be loaded at the same time Therefore, this study will investigate these reduction factors by analyzing three-lane and four-lane steel girder bridges fully loaded, two out of three-lanes, and three out of four-lanes loaded bridges The behavior of these bridges will be investigated by studying the effect of load removal on the lateral wheel load distribution factor The results of this study w ill be used to assess the empirical reduction factors currentK employed by the American .Association of State Highway and Transportation Officials (AASHTO) "Standard Specifications for Highway Bridges (19%) ".--This study will consider critical parameters identified in previous research such as simple (one-span), and continuous (two-span), girder spacing, span length, three-lane bridges and four-lane bridges The finite element method is proposed to analyze the steel girder bridges by using the structural analysis program SAP90 The research will focus on evaluating the maximum lateral wheel load distribution to the steel girders subject to the full (all lanes are loaded) and reduced (bridge partially loaded) design live loading Bridges will be loaded using AASHTO design taicks positioned in the longitudinal direction in order to produce either the maximum positive and/or the maximum negative bending moments.
Single Lane Live Load Distribution Factor for Decked Precast/prestressed Concrete Girder Bridges
Author : John Zhongguo
Publisher :
Page : 448 pages
File Size : 22,77 MB
Release : 2005
Category : Concrete bridges
ISBN :
Book Description
The live load distribution factor (DF) equations provided by AASHTO-LRFD for the decked precast/prestressed concrete (DPPC) girder bridge system do not differentiate between a single or multilane loaded condition. This practice results in a single lane load rating penalty for DPPC girder bridges. The objective of this project is to determine DF equations which accurately predict the distribution factor of the DPPC girder bridge system when it is only subjected to single lane loading. Eight DPPC girder bridges were instrumented. Each bridge was loaded with a single load vehicle to simulate the single lane loaded condition. The experimental data was used to calibrate 3D FE models and 2D grillage models of the DPPC girder bridge system. The calibrated models were used to conduct a parametric study of the DPPC girder bridge system subjected to a single lane loaded condition. Two sets of new equations that describe the single lane loaded distribution factor for both shear and moment forces of these bridges are proposed and compared with AASHTOLRFD DF equations.
Lateral Load Resistance of Diaphragms in Prestressed Concrete Girder Bridges
Author : R. E. Abendroth
Publisher :
Page : 214 pages
File Size : 12,67 MB
Release : 1991
Category : Bridges
ISBN :
Book Description
Each year several prestressed concrete girder bridges in Iowa and other states are struck and damaged by vehicles with loads too high to pass under the bridge. Whether or not intermediate diaphragms play a significant role in reducing the effect of these unusual loading conditions has often been a topic of discussion. A study of the effects of the type and location of intermediate diaphragms in prestressed concrete girder bridges when the bridge girder flanges were subjected to various levels of vertical and horizontal loading was undertaken. The purpose of the research was to determine whether steel diaphragms of any conventional configuration can provide adequate protection to minimize the damage to prestressed concrete girders caused by lateral loads, similar to the protection provided by the reinforced concrete intermediate diaphragms presently being used by the Iowa Department of Transportation. The research program conducted and described in this report included the following: A comprehensive literature search and survey questionnaire were undertaken to define the state-of-the-art in the use of intermediate diaphragms in prestressed concrete girder bridges. A full scale, simple span, restressed concrete girder bridge model, containing three beams was constructed and tested with several types of intermediate diaphragms located at the one-third points of the span or at the mid-span. Analytical studies involving a three-dimensional finite element analysis model were used to provide additional information on the behavior of the experimental bridge. The performance of the bridge with no intermediate diaphragms was quite different than that with intermediate diaphragms in place. All intermediate diaphragms tested had some effect in distributing the loads to the slab and other girders, although some diaphragm types performed better than others. The research conducted has indicated that the replacement of the reinforced concrete intermediate diaphragms currently being used in Iowa with structural steel diaphragms may be possible.
Simplified Load Distribution Factor for Use in LRFD Design
Author : Elisa D. Sotelino
Publisher :
Page : pages
File Size : 13,30 MB
Release : 2004-09-01
Category : Transportation
ISBN : 9781622602407
Book Description
The “S-over” equation for the load distribution factor (LDF) was first introduced in the 1930s in the AASHTO Standard. Finite element studies, however, have shown it to be unsafe in some cases and too conservative in others. In this study, a new simplified equation that is based on the AASHTO LRFD formula and does not require an iterative procedure is developed. The new simplified equation produces LDF values that are always conservative when compared to those obtained from the finite element analyses and are generally greater than the LDF obtained using AASHTO LRFD specification. Therefore, the simplified equation provides a simple yet safe specification for LDF calculation. This study also investigates the effects of secondary elements and bridge deck cracking on the LDF of bridges. The AASHTO LRFD LDF equation was developed based on elastic finite element analysis considering only primary members, i.e., the effects of secondary elements such as lateral bracing and parapets were not considered. Meanwhile, many bridges have been identified as having significant cracking in the concrete deck. Even though deck cracking is a well-known phenomenon, the significance of pre-existing cracks on the live load distribution has not yet been assessed in the literature. First, secondary elements such as diaphragms and parapet were modeled using the finite element method, and the calculated load distribution factors were compared with the code-specified values. Second, the effects of typical deck cracking and crack types that have a major effect on load distribution were identified through a number of nonlinear finite element analyses. Transverse cracking was found to not significantly influence the transverse distribution of moment. Finally, for one of the selected bridges, both concrete cracking and secondary elements are considered to invesitigate their combined effect on lateral load distribution. The increased LDF due to deck cracking is offset by the contributions from the secondary elements. The result is that the proposed simplified equation is conservative and is recommended for determination of LDF.
Challenges in Mechanics of Time-Dependent Materials, Volume 2
Author : Alex Arzoumanidis
Publisher : Springer
Page : 111 pages
File Size : 49,4 MB
Release : 2018-08-09
Category : Science
ISBN : 3319950533
Book Description
Challenges in Mechanics of Time-Dependent Materials, Volume 2 of the Proceedings of the 2018 SEM Annual Conference& Exposition on Experimental and Applied Mechanics, the second volume of eight from the Conference, brings together contributions to this important area of research and engineering. The collection presents early findings and case studies on fundamental and applied aspects of Experimental Mechanics, including papers in the following general technical research areas: Characterization Across Length Scales Extreme Environments & Environmental Effects Soft Materials Damage, fatigue and Fracture Inhomogeneities & Interfaces Viscoelasticity Research in Progress
Investigation of the Impact of Dual-Lane Axle Spacing on Lateral Load Distribution
Author : Brent Phares
Publisher :
Page : 87 pages
File Size : 38,95 MB
Release : 2016
Category : Lateral loads
ISBN :
Book Description
The spacing of adjacent wheel lines of dual-lane loads induces different lateral live load distributions on bridges, which cannot be determined using the current American Association of State Highway and Transportation Officials (AASHTO) Load and Resistance Factor Design (LRFD) or Load Factor Design (LFD) equations for vehicles with standard axle configurations. Current Iowa law requires dual-lane loads to meet a five-foot requirement, the adequacy of which needs to be verified. To improve the state policy and AASHTO code specifications, it is necessary to understand the actual effects of wheel-line spacing on lateral load distribution. The main objective of this research was to investigate the impact of the wheel-line spacing of dual-lane loads on the lateral load distribution on bridges. To achieve this objective, a numerical evaluation using two-dimensional linear elastic finite element (FE) models was performed. For simulation purposes, 20 prestressed-concrete bridges, 20 steel bridges, and 20 slab bridges were randomly sampled from the Iowa bridge database. Based on the FE results, the load distribution factors (LDFs) of the concrete and steel bridges and the equivalent lengths of the slab bridges were derived. To investigate the variations of LDFs, a total of 22 types of single-axle four-wheel-line dual-lane loads were taken into account with configurations consisting of combinations of various interior and exterior wheel-line spacing. The corresponding moment and shear LDFs and equivalent widths were also derived using the AASHTO equations and the adequacy of the Iowa DOT five-foot requirement was evaluated. Finally, the axle weight limits per lane for different dual-lane load types were further calculated and recommended to complement the current Iowa Department of Transportation (DOT) policy and AASHTO code specifications.
