Live Load Effects in Office Buildings

1974 ◽  
Vol 100 (7) ◽  
pp. 1351-1366 ◽  
Author(s):  
Robin K. McGuire ◽  
C. Allin Cornell
2008 ◽  
pp. 335-341 ◽  
Author(s):  
Bala Sivakumar ◽  
Fred Moses ◽  
Michel Ghosn

Author(s):  
Timothy J. McGrath ◽  
Ernest T. Selig ◽  
Timothy J. Beach

A study was undertaken to evaluate the methodology used for the structural design of three-sided culverts with arched top slabs. An 11-m span by 3.4-m rise bridge was instrumented and monitored during installation, under an HS-25 + 30 percent live load and at 6-month intervals for 2 years after installation. The bridge consisted of ten 1.6-m-wide precast segments. Three of the interior segments were instrumented with soil stress cells mounted on the legs of the bridge and with anchor pins for use with a tape extensometer to determine change in shape of the bridge. Survey data were taken on the same three segments and the two adjacent segments. Visual observations were also made to monitor cracking. The live load test was conducted with 0.3 m of cover. Final cover was 0.9 m. The bridge showed less movement under the live load than under the 0.9 m of earth load. The 2-year data show that the shape of the bridge and the soil stresses at the sides of the bridge cycle on an annual basis and that the spans have increased 4 to 8 mm over the 2 years since the completion of construction and appear to be still increasing. Overall, the structural performance of the bridge under earth and live loads was excellent. The correlation between the measured behavior and the computer analysis was good except that the actual live load effects were much smaller than assumed for design. The results of the project support the use of finite-element analysis to design such structures.


2000 ◽  
Vol 1740 (1) ◽  
pp. 108-117 ◽  
Author(s):  
Andrew Lawver ◽  
Catherine French ◽  
Carol K. Shield

The behavior of an integral abutment bridge near Rochester, Minnesota, was investigated from the beginning of construction through several years of service by monitoring more than 180 instruments that were installed in the bridge during construction. The instrumentation was used to measure abutment horizontal movement, abutment rotation, abutment pile strains, earth pressure behind abutments, pier pile strains, prestressed girder strains, concrete deck strains, thermal gradients, steel reinforcement strains, girder displacements, approach panel settlement, frost depth, and weather. In addition to determining the seasonal and daily trends of bridge behavior, live-load tests were conducted. All of the bridge components performed within the design parameters. The effects from the environmental loading of solar radiation and changing ambient temperature were found to be as large as or larger than live-load effects. The abutment was found to accommodate superstructure expansion and contraction through horizontal translation instead of rotation. The abutment piles appeared to be deforming in double curvature, with measured pile strains on the approach panel side of the piles indicating the onset of yielding.


1969 ◽  
Vol 165 (0) ◽  
pp. 41-51
Author(s):  
HIDEO SUGIYAMA ◽  
YOSHIAKI TANAKA
Keyword(s):  

2000 ◽  
Vol 1696 (1) ◽  
pp. 136-143 ◽  
Author(s):  
Andrzej S. Nowak ◽  
Junsik Eom ◽  
Ahmet Sanli

Application of field testing for an efficient evaluation and control of live-load effects on bridges is described. A system is considered that involves monitoring of various parameters, including vehicle weight, dynamic load component, and load effects (moment, shear force, stress, strain) in bridge components, and verification of the minimum load-carrying capacity of the bridge. Therefore, an important part of the study is development of a procedure for measuring live-load spectra on bridges. Truck weight, including gross vehicle weight, axle loads, and spacing, is measured to determine the statistical parameters of the actual live load. Strain and stress are measured in various components of girder bridges to determine component-specific load. Minimum load-carrying capacity is verified by proof load tests. It has been confirmed that live-load effects are strongly site specific and component specific. The measured strains were relatively low and considerably lower than predicted by analysis. Dynamic load factor decreases with increasing static load effect. For fully loaded trucks, it is lower than the code-specified value. Girder distribution factors observed in the tests are also lower than the values specified by the design code. The proof load test results indicated that the structural response is linear with the absolute value of measured strain considerably lower than expected. Field tests confirmed that the tested bridges are adequate to carry normal truck traffic.


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