Influence of the Shear Cap Size and Stiffness on the Distribution of Shear Forces in Flat Slabs

The scope of this paper is to investigate analytically and numerically the influence of shear cap size and stiffness on the distribution of shear forces in flat slabs in a slab–column-connections-reinforced concrete structure. The effect of support (shear cap) stiffness on the calculation of the length of the shear control perimeter according to the available methods is presented. Based on the analysis, the authors indicate in what range of support stiffness the corner concentrations become important in the calculation of the punching resistance. For shear caps with high flexibility (α1 ≤ 0.5), the concentration of internal forces in the corners does not occur. The authors compare the numerical results obtained from the calculation methods and indicate the correlations, which can be useful guidance for structural designers. In the case of large shear caps, the simplified MC2010 method gives a significantly lower value of the effective control perimeter length compared to more accurate methods. This paper is intended to provide scientists, civil engineers, and designers with guidelines on which factors influence punching shear load capacity of the slab–column connections with shear caps.

Older Adult’s Marital Status, Support Exchanges and Psychological Well-being in Everyday Life

Social support exchanges are an integral part of older adults’ well-being. Yet, we know little about how older adults' marital status may influence their support exchanges with different social partners in everyday life, and whether the effect of support exchanges on daily well-being vary by marital status. Adults aged 65+ (N = 278) completed an initial interview about their background and close social networks; then, participants reported whether they provided or received support from their close social partners and rated their psychological well-being for 5 to 6 days. Multilevel logistic models revealed that married older adults were more likely to provide or receive daily support from their close partners than widowed or divorced older adults. However, with respect to specific non-spousal ties, married older adults were less likely to provide support to siblings, friends or others (acquaintances, neighbors) compared to divorced older adults. Although married older adults were more likely to receive support from children than divorced older adults, they were less likely to receive support from siblings and friends compared to widowed or divorced older adults. Furthermore, receiving support from other familial ties (grandchild, other relatives) was associated with reduced daily well-being for widowed older adults whereas married older adults were able to maintain their daily well-being in such situation. Findings highlight the central role siblings and friends play in unmarried older adults' daily support networks and suggest that receiving support could have differential impact on daily well-being depending on older adults’ marital status.

Reinforced Concrete Beam under Support Removal—Parametric Analysis

This paper investigates the behaviour of a reinforced concrete beam under a support removal. A detailed parametric analysis is carried out, covering the effect of support removal rate on dynamic response. The linear elastic and nonlinear inelastic responses are computed and studied in detail. Critical parameters during the structural response are identified. In order to determine the ultimate load, the vertical pushover analysis is performed. The key parameters driving the beam response are assumed as random variables, and respective reliability study makes it possible to check the overall uncertainty of the dynamic response. In particular, the response spectrum measuring the effect of support removal rate has been computed. It has been demonstrated that the critical vertical response occurs when the time of support removal is up to to 17% of the first natural period. The vertical pushover analysis results in obtaining capacity curves and showed the order in which two plastic hinges occur for various load patterns. Finally, the reliability-based sensitivity analysis indicates the geometric cross-section cover and height are the most sensitive parameters of the beam response.