3 edition of Distribution of wheel loads on timber bridges found in the catalog.
Distribution of wheel loads on timber bridges
E C O. Erickson
by U.S. Dept. of Commerce, National Bureau of Standards, Institute for Applied Technology; Distributed by: Clearinghouse for Federal Scientific and Technical Information in [Washington
Written in English
|Other titles||Timber bridges.|
|Statement||by E.C.O. Erickson and K.M. Romstad.|
|Series||Research paper FPL -- 44.|
|Contributions||Romstad, K. M.|
|The Physical Object|
|Pagination||62 p. on 32 l.|
|Number of Pages||62|
Live Load Calculations • Live Load Distribution Factors (LLDF) • How much truck is carried by each beam or strip of slab. • One Axle = 2 wheels • Be careful with wheel vs. axle • Be consistent with LLDF and Live load moment • See Section AASHTO Standard Specifications for Highway Bridges for wheel live load distribution factors. bridges, 15% for other rural and urban interstate bridges, and 10% for bridges in urban areas. Load Distribution for Superstructure Design Figure summarizes load distribution for desi gn of longitudinal supers tructure elements. Load distribution tables and the “lever rule” are approximate methods and intended for most designs.
Transverse nail laminated and transverse plank timber decks are to be rated using the guidelines in Section , Timber Bridges. All other types of bridge decks will be rated in compliance with the applicable guidelines within this manual and the AASHTO code. Hand computations will be acceptable. Subject: Image Created Date: 2/27/ PM.
TIMBER BRIDGE MANUAL EDITION 1 R 0 (i) TABLE OF CONTENTS SECTION ONE 1. TIMBER BRIDGES 1 1. 1 GENERAL 1 1. Scope 1 1. Objectives 1 1. Features 1 1. Limits of Application of the Manual 1 1. Definitions 2 1. 2 STRUCTURE TYPES AND COMPONENTS 4 1. Wood as an Engineering Material 5 1. Timber Bridge (Types) Systems 6. The project was initiated in the mids in order to develop comprehensive specification provisions for distribution of wheel loads in highway bridges. The study was performed in two phases: Phase I concentrated on beam-and-slab and box girder bridges; Phase II concentrated on slab, multibox beam, and spread box beam bridges.
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Timber bridges. Methods and requirements for determining the magnitude and application of individual loads are presented first, followed by discus sions on loading combinations and group loads.
Additional information on load application and distribution related to specific bridge types is given in succeeding chapters on design. DEAD LOADFile Size: KB. Distribution of Wheel Loads on Timber Bridges Erwin Carl Olaf Erickson, K.
Romstad U.S. Department of Commerce, National Bureau of Standards, Institute for. Modern Timber Bridges Meeting Today’s Bridge Needs with Strength, Durability and Beauty Paul C. Gilham, P.E., S.E. Load Distribution Wind & Seismic loads Concepts of Modern Timber Bridges Modern Timber Bridges Design Codes and Specifications Vehicular Bridges.
Distribution of loads in beam and slab bridge floors Joseph Harold Senne Iowa State University and expressions for determining the maximum distribution of wheel loads to the beams. utilizing bridges with timber and concrete floors placed on steel stringers.
Strains were measured in the stringers for both dynamic and static truck : Joseph Harold Senne. one time the static distribution of movable wheel loads in a broad range of bridge types used by today's designers.
This approach gives a uniform approach to the development of specification criteria. The current AASHO specifications for load distribution were es.
Impact Loads. The Impact load on bridge is due to sudden loads which are caused when the vehicle is moving on the bridge. When the wheel is in movement, the live load will change periodically from one wheel to another which results the impact load on bridge. To consider impact loads on bridges, an impact factor is used.
WisDOT Bridge Manual Chapter 45 – Bridge Rating July Introduction Constructed inthe Silver Bridge was an eyebar -chain suspension bridge spanning over.
lift the members into place. Timber bridges tend to deteriorate faster if subjected to high repetitions of heavy loads. Their cost effectiveness should also be evaluated for each site.
Limitations Timber bridges a re not recommended over streams where the year (Q ) frequency flood discharge provides a freeboard less than 24 inches. (wheel lines in adjacent traffic lanes are separated by 4 feet). Figure - Wheel load distribution factor to outside beams, assuming the deck acts as a simple span between supporting beams.
Table - Interior beam live load distribution factors for glulam beams with transverse glulam decks. Longitudinal cracking was found to increase the load distribution factor; the resulting load distribution factor can be up to 17 % higher than the LRFD value.
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. TIMBER BRIDGE MANUAL EDITION 1 R 0 (ii) 6. 6 ENGINEERING EVALUATION 17 6.
Design Specifications 17 6. Concrete Overlay 17 6. Timber Capacities 18 6. Load Distribution for Concrete Overlay Bridges 18 6. Load Distribution and Assumed Span for Concrete Overlay 18 6.
Loads Distribution to Sheeting 18 6. Load Distribution and Assumed Span Length for. The AASHTO Standard Specification (AASHTO ) live load distribution factors for longitudinal glued- laminated timber deck bridges were presented based on wheel loads, or half of the total axle load, carried by a single panel.
The equations used for flexure design are listed in Table 1 for a panel under single or multiple truck loads. The wheel load for the design of this type of deck, for AASHTO HS, is 12, pounds, which has a width of inches.
The timber deck in this design does not provide any additional longitudinal strength to the longitudinal stringers since it only distributes the wheel loads and adds dead load.
cations for Highway Bridges having to do with the distribution of wheel loads on bridge decks. It i s recommende d to engineers, researchers an member of specification writing bodies concerned with bridge design. Its most immediate importance will be to the members of the AASHO Committee on Bridges.
bridges has four beams equally spaced, has tiio interior booms larger than the exterior, and is of composite construction. Among the four bridges the span to spacing ratio varied from to 7*81 and the beam stiffness to slab stiffness ratio varied from 3*0 to * The loads on the laboratory bridges.
The objective of this synthesis is to develop information on distribution of wheel loads on highway bridges. Live-load distribution among the various components of a floor system is one of the key elements in determining member size, strength, and serviceability of a bridge.
Traffic Distribution. Along with load type and repetitions, the load distributions across a particular pavement must be estimated. For instance, on a 6-lane interstate highway (3 lanes in each direction) the total number of loads is probably not distributed exactly equally in both directions.
Lateral live-load distribution factors (LLDFs) for these bridges loaded with farm vehicles are not well known.
Further, the effects associated with farm vehicles have not been considered in the current AASHTO specifications that solely provide codified formulas to calculate LLDFs of timber girders.
I'm trying to rate a simple span wood deck over steel stringer bridge. If I have 8x8 nominal decking with 2" wear on the wheel line. Would you use S/ (4" thick) or S/ (6" or more thick)for wheel load distribution per AASHTO table. thanks, tim. Get this from a library. Distribution of wheel loads on highway bridges.
[Wallace W Sanders; H A Elleby] -- Proposed revisions are presented to those sections of the AASHO specifications for highway bridges having to do with the distribution of wheel loads on bridge decks.
The static distribution of. v = Vertical Dynamic Load (lbs) θ = D 33 x V D w x D = Wheel diameter (in) V = Speed (MPH) P = Static Load (lbs) – Larger wheels impose less influence • Additional dynamic loads from impacts such as caused by wheel flat spots, rail discontinuities (e.g.
frog flangeways), track transitions (e.g. bridge approaches), track condition, etc.Type # 1. Timber Bridge: of 50 mm. thick timber planks are longitudinally placed on both sides of the centre line of the transverse deck for distribution of live loads (wheel loads) over a few decking planks.
50 mm × 50 mm deck stiffeners are also fixed at the bottom of decking planks for the same purpose.A wheel load distribution formula is developed using the results of finite element analysis, which can be used to calculate the flexural stresses in slab‐on‐girder bridges. A typical bridge design was selected, and one parameter was allowed to vary within practical .