Equivalent area of voided slabs

1998 ◽  
Vol 25 (4) ◽  
pp. 797-801 ◽  
Author(s):  
Leslie G Jaeger ◽  
Baidar Bakht ◽  
Gamil Tadros
Keyword(s):  
Simple Expression ◽  
Technical Note ◽  
Axial Stiffness ◽  
Highway Bridge ◽  
Slab Thickness ◽  
Design Code ◽  
Bridge Design ◽  
Equivalent Thickness ◽  
Simple Alternative ◽  
Equivalent Area

In order to calculate prestress losses in the transverse prestressing of voided concrete slabs, it is sometimes convenient to estimate the thickness of an equivalent solid slab. The Ontario Highway Bridge Design Code, as well as the forthcoming Canadian Highway Bridge Design Code, specifies a simple expression for calculating this equivalent thickness. This expression is reviewed in this technical note, and a simple alternative expression, believed to be more accurate, is proposed, along with its derivation. It is shown that the equivalent solid slab thickness obtained from consideration of in-plane forces is also applicable to transverse shear deformations, provided that the usual approximations of elementary strength of materials are used in both cases.Key words: axial stiffness, equivalent area, shear deformation, transverse prestressing, voided slab, slab.

Dynamic loading and testing of bridges in Ontario

1984 ◽  
Vol 11 (4) ◽  
pp. 833-843 ◽  
Author(s):  
J. R. Billing
Keyword(s):  
Dynamic Load ◽  
Dynamic Testing ◽  
Highway Bridge ◽  
Vibration Modes ◽  
Design Codes ◽  
Test Results ◽  
Design Code ◽  
Bridge Design ◽  
Strain Measurements ◽  
Bridge Testing

The Ontario Highway Bridge Design Code (OHBDC) contains provisions on dynamic load and vibration that are substantially different from other codes. Dynamic testing of 27 bridges of various configurations, of steel, timber, and concrete construction, and with spans from 5 to 122 m was therefore undertaken to obtain comprehensive data to support OHBDC provisions. Standardized instrumentation, data acquisition, and test and data processing procedures were used for all bridge tests. Data was gathered from passing trucks, and scheduled runs by test vehicles of various weights. Accelerometer responses were used to determine bridge vibration modes, and dynamic amplifications were obtained from displacement or strain measurements. The form of the provisions adopted for dynamic load and vibration was confirmed by the test results, subject to minor adjustment of values. Observations on the distribution of dynamic load, and its relationship to span length and vehicle weight, may provide a basis for future refinement of the dynamic load provisions. If the stiffness of curbs and barrier walls is not included in deflection calculations, bridges designed by deflection could be penalized. Key words: bridges, vibration, bridge testing, bridge design codes.

Corrigendum: Reliability-based geotechnical design in 2014 Canadian Highway Bridge Design Code

2017 ◽  
Vol 54 (10) ◽  
pp. 1521-1521
Author(s):  
Gordon A. Fenton ◽  
Farzaneh Naghibi ◽  
David Dundas ◽  
Richard J. Bathurst ◽  
D.V. Griffiths
Keyword(s):  
Highway Bridge ◽  
Design Code ◽  
Bridge Design ◽  
Geotechnical Design

scholarly journals Reliability-based geotechnical design in 2014 Canadian Highway Bridge Design Code

2016 ◽  
Vol 53 (2) ◽  
pp. 236-251 ◽  
Author(s):  
Gordon A. Fenton ◽  
Farzaneh Naghibi ◽  
David Dundas ◽  
Richard J. Bathurst ◽  
D.V. Griffiths
Keyword(s):  
Structural Engineering ◽  
Highway Bridge ◽  
Design Code ◽  
Bridge Design ◽  
Limit States ◽  
Simple Fact ◽  
Codes Of Practice ◽  
Geotechnical Design ◽  
Civil Codes ◽  
Load And Resistance Factor

Canada has two national civil codes of practice that include geotechnical design provisions: the National Building Code of Canada and the Canadian Highway Bridge Design Code. For structural designs, both of these codes have been employing a load and resistance factor format embedded within a limit states design framework since the mid-1970s. Unfortunately, limit states design in geotechnical engineering has been lagging well behind that in structural engineering for the simple fact that the ground is by far the most variable (and hence uncertain) of engineering materials. Although the first implementation of a geotechnical limit states design code appeared in Denmark in 1956, it was not until 1979 that the concept began to appear in Canadian design codes, i.e., in the Ontario Highway Bridge Design Code, which later became the Canadian Highway Bridge Design Code (CHBDC). The geotechnical design provisions in the CHBDC have evolved significantly since their inception in 1979. This paper describes the latest advances appearing in the CHBDC along with the steps taken to calibrate its recent geotechnical resistance and consequence factors.

Deep foundation design in the new Ontario Highway Bridge Design Code: Discussion

1983 ◽  
Vol 20 (4) ◽  
pp. 858-859
Author(s):  
Baidar Bakht ◽  
Leslie G. Jaeger ◽  
Roger A. Dorton
Keyword(s):  
Highway Bridge ◽  
Design Code ◽  
Bridge Design ◽  
Foundation Design ◽  
Deep Foundation

Losses in partially prestressed concrete

1988 ◽  
Vol 15 (5) ◽  
pp. 890-899
Author(s):  
B. DeV. Batchelor ◽  
Jayanth Srinivasan ◽  
Mark F. Green
Keyword(s):  
Key Words ◽  
Prestressed Concrete ◽  
Effective Modulus ◽  
Highway Bridge ◽  
Design Code ◽  
Bridge Design ◽  
Prestress Losses ◽  
Concrete Members ◽  
Modulus Method

The calculation of prestress losses by the age-adjusted effective modulus method is analyzed and compared with the Ontario highway bridge design code predictions for partially prestressed concrete. Specifically, the effect of nonprestressed reinforcement on prestress losses is studied. The age-adjusted effective modulus method for calculating prestress losses is outlined, and plots of prestress losses versus partial prestressing ratio are presented and analyzed. It is shown that prestress losses decrease with increasing amounts of nonprestressed reinforcement. Also, the Ontario highway bridge design code expressions, which are intended for use with fully prestressed sections, are not suitable for use in the design of partially prestressed concrete members. Key words: concrete (prestress), design, partial prestressing, prestress losses.

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