Laboratory Testing of Stress-Laminated Wood Decks on Steel Beams

1997 ◽  
Vol 1575 (1) ◽  
pp. 47-52
Author(s):  
Barry Dickson ◽  
Hota GangaRao ◽  
Vijith Vijayachandran
Keyword(s):  
Load Distribution ◽  
Laboratory Testing ◽  
Static Load ◽  
Theoretical Calculations ◽  
Construction Cost ◽  
Transverse Load ◽  
Steel Beams ◽  
Composite Action ◽  
Static Testing ◽  
Load Tests

Four different stress-laminated wood decks were laboratory-tested to measure composite action between deck and steel beams, transverse load distribution, performance of connectors, and deck construction cost. The models were subjected to cyclic loading varying from 9 to 89 kN. Static load tests were conducted after every 100,000 cycles. During static testing, strains and deflections in the beams were measured at 22, 44, 67, and 89 kN. The loss of tension in the connectors was also monitored after every 100,000 cycles. The readings were used to compare the composite action, load distribution, and tension loss in connectors. Load distribution values were verified with theoretical calculations.

Load distribution in continuous composite bridges

1983 ◽  
Vol 10 (3) ◽  
pp. 384-395 ◽  
Author(s):  
John B. Kennedy ◽  
N. F. Grace
Keyword(s):  
Load Distribution ◽  
Transverse Load ◽  
Design Parameters ◽  
Skew Angle ◽  
Composite Action ◽  
Transverse Cracking ◽  
Composite Bridges ◽  
Current Design ◽  
Bridge Models ◽  
Concrete Deck

The influence of transverse diaphragms on the load distribution in composite bridges has been minimized in current design codes. Tests have shown that when diaphragms having an I-section are rigidly connected to the longitudinal girders, a rigid gridwork is formed; this gridwork in composite action with the concrete deck distributes the wheel loads on the bridge in an orthotropic manner. In this paper, the influences of the number of diaphragms, aspect ratio, skew, and cracking of the concrete deck on the transverse load distribution in continuous composite bridges are examined. The theoretical results are verified and substantiated by tests on two 1/8-scale bridge models. The results indicate that such diaphragms, rigidly connected to longitudinal girders, significantly enhance the transverse load distribution, and thus a reduction in the design load for the girders results; the degree of this enhancement increases with increase in the width as well as the skew angle of the bridge. Furthermore, transverse cracking of the concrete deck at the intermediate support(s) does not appear to influence significantly the transverse distribution of the design parameters.

Laboratory Testing of Low-Volume Road Bridge Alternative

1998 ◽  
Vol 1624 (1) ◽  
pp. 148-159 ◽  
Author(s):  
B. M. Phares ◽  
T. J. Wipf ◽  
F. W. Klaiber
Keyword(s):  
Load Distribution ◽  
Laboratory Testing ◽  
Concrete Surface ◽  
Small Scale ◽  
Steel Beams ◽  
Bridge Model ◽  
Low Volume Roads ◽  
Low Volume ◽  
Lateral Load Distribution ◽  
Concrete Deck

In Iowa there are over 20,000 bridges on the secondary road system. The majority of these bridges are under the jurisdiction of county engineers with limited budgets; therefore many county engineers design and construct their own short-span bridges with their own labor force. The objective of this research is to perform laboratory testing on a bridge alternative that counties can design and construct. This concept involves the fabrication of precast units composed of two steel beams connected by a thin concrete deck. The concrete deck thickness is limited so that the units can be fabricated at one location and then transported to the bridge site. The number of units required is obviously a function of the width of bridge desired. After the precast units have been connected, an additional concrete deck is placed. The concrete surface of the units is scarified so that the two layers of concrete are bonded together, thus providing the required deck thickness. Since this bridge replacement system is primarily intended for use on low-volume roads, the precast units could be constructed with new or used steel beams. The laboratory testing program consisted of a series of small-scale tests on different types of precast deck connections, “handling strength” tests of the precast units, a series of tests on the model bridge with only the precast portion of the deck in place, and a series of tests on the fully constructed model bridge. For the bridge model tested [ L = 9750 mm (32 ft), W = 6400 mm (21 ft)], five precast connectors gave the desired lateral load distribution; the addition of the cast-in-place deck significantly improved the load distribution characteristics of the bridge system. The units developed and tested result in a simple-span bridge for low-volume roads that is relatively easy to construct.

Research on Static Load Tests of Damaged Bridge Strengthened with Pre-Stressed HFRP

2014 ◽  
Vol 1079-1080 ◽  
pp. 258-265
Author(s):  
Chen Ning Cai ◽  
Shan He ◽  
Li Na Liu ◽  
Shi Kun Ou
Keyword(s):  
Static Load ◽  
Flexural Rigidity ◽  
Fiber Reinforced Polymer ◽  
Test Results ◽  
Structural Members ◽  
Fiber Reinforced ◽  
Hybrid Fiber ◽  
Reinforced Polymer ◽  
Glass Fiber Reinforced ◽  
Load Tests

Thispaper presents an experimental study to strengthen an existing bridge usingpre-stressed carbon fiber reinforced polymer (CFRP) and glass fiber reinforced polymer(GFRP) materials. The method using pre-stressed hybrid fiber reinforced polymer(HFRP) to strengthened structural members is an emerging pre-stressed strengtheningtechnology. In this study, experimental data selected from result of staticloading test conducted to hollow slabs with CFRP/GFRP has been compared with specimenswithout strengthening. Test results showed that the strengthening methoddeveloped in this study could effectively reduce the stress in hollow slab,improving the flexural rigidity and inhibiting the concrete from fracture.

scholarly journals Pressure Orientation-Dependent Recovery of 3D-Printed PLA Objects with Varying Infill Degree

Polymers ◽  
2021 ◽  
Vol 13 (8) ◽  
pp. 1275 ◽  
Author(s):  
Guido Ehrmann ◽  
Andrea Ehrmann
Keyword(s):  
Shape Memory ◽  
Fused Deposition Modeling ◽  
Static Load ◽  
Shape Memory Polymer ◽  
Applied Pressure ◽  
Poly Lactic Acid ◽  
Fused Deposition ◽  
Deposition Modeling ◽  
Load Tests ◽  
3D Printed

Poly(lactic acid) is not only one of the most often used materials for 3D printing via fused deposition modeling (FDM), but also a shape-memory polymer. This means that objects printed from PLA can, to a certain extent, be deformed and regenerate their original shape automatically when they are heated to a moderate temperature of about 60–100 °C. It is important to note that pure PLA cannot restore broken bonds, so that it is necessary to find structures which can take up large forces by deformation without full breaks. Here we report on the continuation of previous tests on 3D-printed cubes with different infill patterns and degrees, now investigating the influence of the orientation of the applied pressure on the recovery properties. We find that for the applied gyroid pattern, indentation on the front parallel to the layers gives the worst recovery due to nearly full layer separation, while indentation on the front perpendicular to the layers or diagonal gives significantly better results. Pressing from the top, either diagonal or parallel to an edge, interestingly leads to a different residual strain than pressing from front, with indentation on top always firstly leading to an expansion towards the indenter after the first few quasi-static load tests. To quantitatively evaluate these results, new measures are suggested which could be adopted by other groups working on shape-memory polymers.

Investigation of Grouted Coupler Connection Details for Accelerated Bridge Construction

2021 ◽  
pp. 036119812199939
Author(s):  
Brent Phares ◽  
Yoon-Si Lee ◽  
Travis K. Hosteng ◽  
Jim Nelson
Keyword(s):  
Crack Width ◽  
High Performance ◽  
Static Load ◽  
High Performance Concrete ◽  
Precast Concrete ◽  
Chloride Penetration ◽  
Load Testing ◽  
Test And Evaluation ◽  
Load Tests ◽  
Precast Elements

This paper presents a laboratory investigation on the performance of grouted rebar couplers with the connection details similar to those utilized on the precast concrete elements of the Keg Creek Bridge on US 6 in Iowa. The testing program consisted of a series of static load tests, a fatigue test, and evaluation of the chloride penetration resistance of laboratory specimens. The goal of this testing was to evaluate the ability of the grouted rebar couplers to develop flexural capacity at the joint between the precast elements as well as the durability of the connection. For structural load testing, seven full-scale specimens, each with #14 epoxy-coated rebars spliced by epoxy-coated grouted couplers, were fabricated and tested in three different loading cases: four-point bending, axial tension plus bending, and a cyclic test of the system in bending. The static load testing demonstrated that the applied axial load had a minimal effect on the formation of cracks and overall performance of the connection. When ultra-high performance concrete was used as a bedding grout, the initiation of crack was slightly delayed but no considerable improvement was observed in the magnitude of the crack width during loading or the crack closure on unloading. The results of the seventh specimen, tested in fatigue to 1 million cycles, showed little global displacement and crack width throughout the test, neither of which expanded measurably. No evidence of moisture or chloride penetration was detected at the grouted joint during the 6-month monitoring.

A Comparison of Analytical Predictions With Experimental Measurements of Transmission Error of Misaligned Loaded Gears

1992 ◽  
Author(s):  
Harsh Vinayak ◽  
Donald R. Houser
Keyword(s):  
Experimental Data ◽  
Load Distribution ◽  
Theoretical Calculations ◽  
Data Acquisition System ◽  
Transmission Error ◽  
Test Facility ◽  
Experimental Measurements ◽  
Gear Pair ◽  
Prediction Program ◽  
Dynamic Transmission Error

Abstract This paper deals with the experimental study of dynamic transmission error of a gear pair. Two aspects of the experiment are discussed : 1) design of the test facility and data acquisition system and 2) comparison of transmission error and load distribution with experimental data. Several gears were tested under varying misalignments. A prediction program LDP (Load distribution Program) was used for theoretical calculations of dynamic transmission error.

Sign in / Sign up

Export Citation Format

Share Document