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Highlights: [•] Fatigue tests were conducted to develop a repair procedure for damaged sign structures. [•] Conventional welded sleeve connections showed a low fatigue resistance. [•] A gusset-repaired specimen showed a low fatigue resistance. [•] Steel-jacketing with cement grouting significantly improved the fatigue resistance. [•] The use of a welded steel cone significantly improved the fatigue resistance. [ABSTRACT FROM AUTHOR]

Cantilevered steel sign structures are widely used for on-premises freestanding signs. A welded sleeve connection detail is commonly used to splice pipes of different diameters. This type of structure can be flexible and the connections are vulnerable to fatigue cracking attributable to wind-induced vibration. Fatigue has not been considered in design, although the connection has an inherently low fatigue resistance. To investigate the cause of failure at the sleeve connection and to mitigate the problem, a study of 10 sample failure cases and a series of finite-element analyses were performed. The finite-element analyses showed that the actual load-transfer mechanism in the sleeve connection was not very consistent with that assumed in design. In addition, very high-stress concentration caused the weld-toe crack to propagate into the pipe section. The common practice of strengthening the connection by welded gusset plates did not alleviate the problem. A frequency analysis indicated that the second-mode resonance because of wind-induced vortex shedding may cause a large number of damage cycles. Two alternative connection details were proposed to mitigate weld cracking. [ABSTRACT FROM AUTHOR]

Cantilevered steel sign structures, commonly used to support freestanding signs, are flexible, have low damping, and can be prone to fatigue-type failure as a result of wind-induced vibration. A sleeve connection, involving horizontal ring plates with two-sided fillet welds welded to the upper pipe and slot welds to connect the lower ring plates to the lower pipe, is commonly used to splice the upper and lower pipes of different diameters. Although the majority of these structures have performed well in long-term use, some structures have been damaged or destroyed as a result of cracking at the weld toe of the sleeve connections. A testing program was developed to evaluate the relative fatigue life of conventional and alternative connection details. Testing demonstrated that conventional welded connections had a short fatigue life. A revised sleeve connection detail incorporating a one-sided fillet weld detail at the critical joint was effective in enhancing the fatigue performance. Replacing slot welds by cement grouting the gap between two pipes significantly increased the fatigue life. Using a welded cone to provide a smooth transition between the pipes also showed improved performance. A tapered slip-joint connection that required no welded joints between the pipe sections provided the best fatigue performance. [ABSTRACT FROM AUTHOR]

International Roughness Index (IRI) is a key parameter in pavement performance evaluation. This study investigates developing a reliable prediction model that can be used to estimate IRI of rigid pavements using innovative machine learning techniques. Optimally Pruned Extreme Learning Machine (OP-ELM) and Wavelet analysis are integrated to improve the OP-ELM results and design a novel hybrid Wavelet-OPELM (WOPELM) model for the IRI prediction. The proposed model is compared statistically to the OP-ELM and conventional feed-forward Artificial Neural Network (ANN) as well as regression model with respect to their efficiency to predict IRI of jointed plain concrete pavement (JPCP) sections in USA. The relevant data was collected from the Long-Term Pavement Performance (LTPP) database. Eight input variables, initial IRI, pavement age, transverse cracks, percent joints spalled, flexible and rigid patching areas, total joint faulting, freeze index, and percent subgrade passing No. 200 U.S. sieve, are assessed and used to predict the IRI. The results show that the initial IRI, total joint faulting, and freezing index are the most significant parameters for IRI prediction. The WOPELM is found to be a robust and more accurate modelling technique compared to OP-ELM, ANN, and regression for IRI prediction with only a 7% prediction error. [ABSTRACT FROM AUTHOR]

Abstract As the design methodology of the corrugated steel shear wall (CSSW) has not yet been included in the design standards, this paper presents a step-by-step design procedure based on the corrugated panel-frame interaction (CPFI). To ensure that the plastic hinges occur at the beam ends and not within the beam span or in the columns, a reduced beam section (RBS) connection was used in steel plate shear walls (SPSWs). In this paper, the corrugated steel shear wall with a reduced boundary beam section (RBS-CSSW) is presented as a promising type of lateral-load‐resisting system. Analytical equations were proposed to estimate the strength of RBS-CSSW based on the frame plastic hinge development considering the interactive shear buckling stress in the corrugated panel. The equations of strength estimation for RBS-CSSW were also evaluated by comparing their results with the numerical results of the two models. The comparison showed that the strength based on the proposed analytical equations were accurate (with more than 95% accuracy) compared to the strength from the FE pushover analyses for the two models. Highlights • The step-by-step design guideline based on the corrugated panel-frame interaction is proposed. • The implementation of the reduced beam section with corrugated plate is investigated. • The strength equation for corrugated steel shear walls with reduced beam section is proposed. • The computational finite element analysis shows the proposed equations has 95% accuracy. [ABSTRACT FROM AUTHOR]

In this study, stub columns subjected to concentric and eccentric loads were tested to check the applicability of the current local stability criteria to 800MPa high-strength steel (HSA800) recently developed in Korea. The key test variables in the concentrically loaded tests included the plate-edge restraints and the width-to-thickness ratio. Specimens made of ordinary steel (SM490) were also tested for comparison purposes. Eccentrically loaded stub column tests were conducted for a range of the P-M combinations by controlling the loading eccentricity. All the concentrically loaded specimens with non-compact and slender sections developed sufficient strengths according to the current local stability criteria. All the eccentrically loaded specimens with non-compact H-sections also exhibited a sufficient P-M interaction strength even higher than that of compact H-section counterparts. The experimental P-M interaction strength was very accurately predicted with the strain compatibility method by using the measured stress-strain curve, or by explicitly considering early strain-hardening property of high strength steel. Residual stresses were also measured by using the non-destructive indentation method to see their dependency or independency on the yield stress of steel material. The measured results of this study again indicated that the magnitude of residual stresses bears no strong relation to the yield stress of steel material, implying that the impact of residual stress on inelastic local buckling of high strength steels is less. [ABSTRACT FROM AUTHOR]