Experimental procedures for the determination of physical properties of viscoelastic materials are discussed in this paper. Two well-known methods—a standard ASTM method and the other based on indirect measures—are compared to the method proposed here that uses direct measures of forces and response in terms of displacements or accelerations. Two kinds of materials were tested using these three methods; some conclusions, stressing the advantages of the suggested methodology, are presented at the end of the paper.

In this paper is proposed a set of empirical equations for parameters and initial conditions of a damped bipedal model with compliant legs. The parameters of the bipedal model are estimated by fitting numerical and experimental walking forces. Sixteen volunteers are recruited to participate in experimental tests to walk on a prototype footbridge. The vertical ground reaction forces (GRFs) induced by pedestrians are recorded by force plates and the accelerations of the structure are recorded by accelerometers. Multiple simulations within certain ranges of input parameters are performed to identify the best matches between the model’s predictions and experimentally measured GRFs. Based on empirical data, regression equations are proposed as functions of pedestrian’s mass, height, and walking speed. To validate the proposed equations, the experimental tests are simulated, and the predicted structure dynamic responses are compared to measured vibrations on the footbridge. To generate a more realistic pedestrian loading, the gait speed of each step is randomized within a range to reproduce the step-by-step variations. The results of this study validate the suitability of a set of parameters selected for the bipedal model, for use in predicting loads induced by humans and estimating the vibration response of pedestrian structures.

The damage identification problem in offshore platforms, specifically in jacket platforms, has been studied since the seventies. In spite of the effort dispended, there is still no spread out methodology that can be applied in this kind of structure, due its specific characteristics (structural complexity, load and operational conditions, etc.). The development of such methods would be extremely useful to preview structural failures, once this kind of structures is almost completely under water. Most of the developed methods for damage identification use modal parameters, by comparisons of different structural time conditions, and the damage may be expressed through the observed discrepancy. This paper presents a methodology to locate damage based on an iterative method. It was developed an optimization software which uses the Goal Programming Technique to choose the best set of variables that minimizes the difference between experimental and numerical Frequency Response Functions (FRFs), which can better represent the structure situation. Some numerical simulations were performed on a scaled fixed oil platform model to verify the efficiency of the method. The results show that such method is efficient when damages are restricted to a set of optimization variables.