scholarly journals A Review of Similitude Methods for Structural Engineering

2019 ◽  
Vol 71 (3) ◽  
Author(s):  
Alessandro Casaburo ◽  
Giuseppe Petrone ◽  
Francesco Franco ◽  
Sergio De Rosa

Similitude theory allows engineers, through a set of tools known as similitude methods, to establish the necessary conditions to design a scaled (up or down) model of a full-scale prototype structure. In recent years, to overcome the obstacles associated with full-scale testing, such as cost and setup, research on similitude methods has grown and their application has expanded into many branches of engineering. The aim of this paper is to provide as comprehensive a review as possible about similitude methods applied to structural engineering and their limitations due to size effects, rate sensitivity phenomena, etc. After a brief historical introduction and a more in-depth analysis of the main methods, the paper focuses on similitude applications classified, first, by test article, then by engineering fields.

Author(s):  
Colton Sheets ◽  
Robert Rettew ◽  
Chris Alexander ◽  
Tanya Axenova

The increasing use of composite repair systems in critical and complex applications has brought greater scrutiny to their design and performance. This has been especially true in high-temperature, immersed environment applications where ambient temperature test results with industry standard de-rating factors are all that is available for design. Since this approach does not always adequately capture environmental effects or the performance of composite systems at elevated temperatures, it is beneficial to perform full-scale testing which accurately replicates the in-situ application. In order to accomplish this, a full-scale testing program was developed that subjected multiple composite repair systems to internal and external loads at temperatures up to 120 °C with and without water immersion. This program involved the reinforcement of 12.75-inch × 0.375-inch pipe samples that had simulated corrosion defects. Full-scale load and pressure testing was conducted to simulate the long-term performance of the composite repair systems in the environmental conditions of the application. A strain based performance threshold of 0.4% strain at 120 °C and 100% SMYS was used to develop a competitive program that ranked the participating systems and reduced the number of acceptable repairs from six down to three. This approach increased the efficiency of the full-scale testing and allowed for more in-depth analysis of the top-performing systems. The results of the full-scale testing of six composite repair systems at elevated temperature allowed for a quantitative measure of their effectiveness under in-situ conditions. Several of the systems were shown to provide inadequate reinforcement under these conditions; however, it was also observed that appropriately designed and installed systems are capable of meeting the intense demands of elevated temperature, harsh-service conditions.


Author(s):  
Craig Taylor ◽  
Sreekanta Das ◽  
Laurie Collins ◽  
Muhammad Rashid

Very few studies have been conducted concerning fatigue in steel line pipe and fewer using full-scale testing. Further, at the time of this study, no research on full-scale testing was available in open literature regarding fatigue behavior of line pipe with longitudinal cracks, despite being considered more critical than the line pipe with cracks oriented in the circumferential direction. In the current research work, fatigue crack growth was investigated in NPS 20, API 5L X-70 grade, electrical resistance welding (ERW) straight-seam steel line pipes in the base metal and at the weld seam for various orientations. It was found that there was no significant difference between fatigue crack growth in the base metal and at the weld seam for the tested stress ratio. Increasing the angle of inclination of the crack with respect to the weld line was found to decrease the rate of fatigue crack growth due to a decrease in the mode I stress component. Finally, it was observed that despite the difference in fatigue crack growth rates, the crack aspect ratios were nearly identical for all cracks at the same crack depth.


Author(s):  
William F. Williams

The purpose of this project was to design and test a new bolt-down bollard system that meets the requirements of American Standards for Testing Materials (ASTM) Designation F2656-15 M50/P1 impact conditions. The test installation consisted of three vertical 10-in. diameter (nominal) bollards with welded base plates bolted to a shallow reinforced concrete foundation. The foundation for this system was sized to reduce the foundation embedment. Shallow foundations are often necessary for use in cities and urban areas where utilities can conflict with deeper foundations. Standard common members and materials were used in the installation to accommodate fabrication and installation in locations all over the world. The bollards can be removed to provide access if necessary. Full-scale testing was performed on the bolt-down bollard system. The bollard system design for this project successfully met the requirements of M50/P1 with a total payload penetration of less than 1 m. The new bollard design successfully met all the performance requirements for ASTM F2656-15 M50/P1. Details of the design and testing of the bolt-down bollard system are provided in this paper. Crash-testing videos and additional information on the design and full-scale testing will be provided in the presentation.


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