Control of Live Load on Bridges

2000 ◽  
Vol 1696 (1) ◽  
pp. 136-143 ◽  
Author(s):  
Andrzej S. Nowak ◽  
Junsik Eom ◽  
Ahmet Sanli
Keyword(s):  
Dynamic Load ◽  
Carrying Capacity ◽  
Load Test ◽  
Load Factor ◽  
Live Load ◽  
Load Carrying Capacity ◽  
Load Effect ◽  
Vehicle Weight ◽  
Load Carrying ◽  
Load Effects

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.

scholarly journals Strengthening of RCC Beams in Shear by Using SBR Polymer-Modified Ferrocement Jacketing Technique

2018 ◽  
Vol 2018 ◽  
pp. 1-16 ◽  
Author(s):  
Rajinder Ghai ◽  
Prem Pal Bansal ◽  
Maneek Kumar
Keyword(s):  
Carrying Capacity ◽  
Shear Failure ◽  
Ultimate Load ◽  
Load Test ◽  
Wire Mesh ◽  
Styrene Butadiene Rubber ◽  
Shear Load ◽  
Butadiene Rubber ◽  
Load Carrying Capacity ◽  
Load Carrying

There is a common phenomenon of shear failure in RCC beams, especially in old buildings and bridges. Any possible strengthening of such beams is needed to be explored that could strengthen and make them fit for serviceable conditions. The present research has been made to determine the performance of predamaged beams strengthened with three-layered wire mesh polymer-modified ferrocement (PMF) with 15% styrene-butadiene-rubber latex (SBR) polymer. Forty-eight shear-designed and shear-deficient real-size beams were used in this experimental work. Ultimate shear load-carrying capacity of control beams was found at two different shear-span (a/d) ratios 1 and 3. The sets of remaining beams were loaded with different predetermined damage levels of 45%, 75%, and 95% of the ultimate load values and then strengthened with 20 mm thick PMF. The strengthened beams were then again tested for ultimate load-carrying capacity by conducting the shear load test at a/d = 1 and 3. As a result, the PMF-strengthened beams showed restoration and enhancement of ultimate shear load-carrying capacity by 5.90% to 12.03%. The ductility of strengthened beams was improved, and hence, the corresponding deflections were prolonged. On the other hand, the cracking pattern of PMF-strengthened beams was also improved remarkably.

scholarly journals A New Methodology for Solving Trajectory Planning and Dynamic Load-Carrying Capacity of a Robot Manipulator

2016 ◽  
Vol 2016 ◽  
pp. 1-28 ◽  
Author(s):  
Wanjin Guo ◽  
Ruifeng Li ◽  
Chuqing Cao ◽  
Xunwei Tong ◽  
Yunfeng Gao
Keyword(s):  
Trajectory Planning ◽  
Dynamic Load ◽  
Carrying Capacity ◽  
Robot Manipulator ◽  
Time Interval ◽  
Planning Problem ◽  
Load Carrying Capacity ◽  
Objective Functions ◽  
Decision Variables ◽  
Load Carrying

A new methodology using a direct method for obtaining the best found trajectory planning and maximum dynamic load-carrying capacity (DLCC) is presented for a 5-degree of freedom (DOF) hybrid robot manipulator. A nonlinear constrained multiobjective optimization problem is formulated with four objective functions, namely, travel time, total energy involved in the motion, joint jerks, and joint acceleration. The vector of decision variables is defined by the sequence of the time-interval lengths associated with each two consecutive via-points on the desired trajectory of the 5-DOF robot generalized coordinates. Then this vector of decision variables is computed in order to minimize the cost function (which is the weighted sum of these four objective functions) subject to constraints on joint positions, velocities, acceleration, jerks, forces/torques, and payload mass. Two separate approaches are proposed to deal with the trajectory planning problem and the maximum DLCC calculation for the 5-DOF robot manipulator using an evolutionary optimization technique. The adopted evolutionary algorithm is the elitist nondominated sorting genetic algorithm (NSGA-II). A numerical application is performed for obtaining best found solutions of trajectory planning and maximum DLCC calculation for the 5-DOF hybrid robot manipulator.

Evaluation of Dynamic Load-Carrying Capacity for Free-Floating Space Manipulators

2015 ◽  
Vol 713-715 ◽  
pp. 795-799 ◽  
Author(s):  
Yong Liu ◽  
Qing Xuan Jia ◽  
Gang Chen ◽  
Han Xu Sun ◽  
Jun Jie Peng
Keyword(s):  
Dynamic Load ◽  
Carrying Capacity ◽  
Function Method ◽  
Feasible Region ◽  
Penalty Function Method ◽  
Load Carrying Capacity ◽  
One Dimensional ◽  
Space Manipulators ◽  
Load Carrying ◽  
Point To Point

Two kinds of dynamic load-carrying capacity (DLCC) evaluation methods for free-floating space manipulators (FFSM) in two typical on-orbit operating missions are proposed in this paper. DLCC evaluation is transformed into nonlinear programming problem (NPP) by introducing load-carrying coefficient to measure DLCC: in point-to-point task, penalty function method is adopted to approach the boundary of feasible region rapidly, then DLCC can be obtained through following iterations; in trajectory tracking task, NPP is solved by using multiple one-dimensional search, the dynamic load-carrying coefficient in discontinuous feasible region can be quickly solved through adjusting the searching boundary constantly. The effectiveness of the mentioned methods is verified by simulations.

scholarly journals Ultimate Capacity of Vertical Pile Subjected to Combination of Vertical and Lateral Load

2019 ◽  
Vol 8 (9S2) ◽  
pp. 647-652
Keyword(s):  
Carrying Capacity ◽  
Ultimate Load ◽  
Lateral Load ◽  
Load Factor ◽  
Load Carrying Capacity ◽  
Vertical Load ◽  
Ultimate Capacity ◽  
Inclined Load ◽  
Load Carrying ◽  
Ultimate Load Carrying Capacity

Pile under general condition is subjected to combination of vertical and lateral loads In the analytical approaches to predict the load-displacement responses of a pile under central inclined load, it is assumed that the lateral displacement of the pile head is independent by the vertical load factor of the inclined load. Similarly, while estimating the ultimate resistance it is considered that the vertical load factor of the inclined load does not influence the ultimate lateral resistance of the pile during determination of ultimate load carrying capacity of vertical pile. In the present work, an empirical relation has been developed to predict the ultimate load carrying capacity of vertical piles subjected to combination of both vertical and lateral load in cohesion less soil. Effect of lateral load on vertical load deflection behavior of vertical piles when axial loads are present are discussed through several experimental results obtained from tests on model piles. Ultimate capacity is found to be a continuous function of ultimate lateral load, ultimate vertical load capacity and tangent of angle of resultant load made with vertical axis of pile.

scholarly journals Dynamic Carrying Capacity Analysis of Double-Row Four-Point Contact Ball Slewing Bearing

2015 ◽  
Vol 2015 ◽  
pp. 1-7 ◽  
Author(s):  
Yunfeng Li ◽  
Di Jiang
Keyword(s):  
Dynamic Load ◽  
Carrying Capacity ◽  
Point Contact ◽  
Design Parameters ◽  
Load Carrying Capacity ◽  
Double Row ◽  
Slewing Bearing ◽  
Load Carrying ◽  
Bearing Design ◽  
Capacity Surface

Carrying capacity is the most important performance index for slewing bearings. Maximizing the carrying capacity of slewing bearing is one pursuing goal for the bearing designer; this is usually realized by optimizing the design parameters. A method of analyzing the carrying capacity of double-row four-point contact ball slewing bearing by using dynamic carrying capacity surfaces was proposed in this paper. Based on the dynamic load carrying capacity surface of the slewing bearing, the effect of changes of the bearing design parameters, such as axial clearance, raceway groove radius coefficient, and contact angle, on the dynamic carrying capacity of the slewing bearing was researched; the trend and the degree of the effect of the micro changes of the bearing design parameters on the dynamic load carrying capacity of the bearing were discussed, and the results provide the basis for optimizing the design parameter of this type of slewing bearing.

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