41,381 research outputs found

    Control mechanisms and perceived organizational support: exploring the relationship between new and traditional forms of control

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    Purpose: Taking into account the need to make a clearer distinction between traditional and new organizational controls, this paper aims to investigate similarities and differences between those two forms and explore the extent to which new forms of control can be operationalized from a quantitative point of view. Design/methodology/approach: Suggesting that new organizational controls can be understood also in light of quantitative paradigms, we develop and test a scale to measure the existence of these types of controls, examine its construct validity and evaluate its convergent validity. Findings: The theoretical dimensions of new controls have empirical correspondence. Input and behaviour controls are strongly associated with the promotion of values and beliefs in organizations. New controls become responsible for employees’ acceptance of companies’ management, an aspect measured by Perceived-Organizational-Support (POS)

    Out-of-plane seismic response of stone masonry walls: experimental and analytical study of real piers

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    This paper presents the application of an existing simplified displacement-based procedure to the characterization of the nonlinear force-displacement relationship for the out-of-plane behaviour of unreinforced traditional masonry walls. According to this procedure, tri-linear models based on three different energy based criteria were constructed and confronted with three experimental tests on existing stone masonry constructions. Moreover, a brief introduction is presented regarding the main characteristics of the in situ cyclic testing recently carried out using distributed loads, as well as results obtained during the experimental campaigns performed. The comparison between the experimental and the analytical results are presented and discussed

    Experimental response of RC columns built with plain bars under unidirectional cyclic loading

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    A large number of existing reinforced concrete (RC) buildings structures were designed and built before mid-70’s, when the reinforcing bars had plain surface and prior to the enforcement of the modern seismic-oriented design philosophies. This paper describes a series of unidirectional cyclic tests performed on seven full-scale columns built with plain reinforcing bars, without adequate reinforcement detailing for seismic demands. The specimens have different reinforcing steel details and different cross sections. A further monotonic test was also carried out for one of the specimens and an additional column, built with deformed bars, was cyclically tested for comparison with the results for the specimens with plain bars. The main experimental results are presented and discussed. The influence of bond properties on the column behaviour is evidenced by differences observed between the cyclic response of similar specimens with plain and deformed bars. The influence of reinforcement amount and displacement history on the column response is also investigated

    Out-of-plane in situ cyclic testing of unreinforced stone masonry walls with distributed loads

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    The present paper reports an in situ experimental test campaign carried out on existing buildings, in order to investigate the seismic behaviour of traditional masonry walls subject to out-of-plane loads. For the testing proposes, an experimental test setup based on a selfequilibrated scheme was developed and optimized to be applied in situ in two specimens on original and strengthened conditions. The obtained results are presented and carefully discussed namely from the reinforcement solutions’ efficiency point-of-view, as well as compared to previous experimental data obtained for the same type of masonry walls. Additionally, a simplified linearized displacement-based procedure was adapted in order to characterize the nonlinear force-displacement relationship for unreinforced traditional masonry walls and to analytically predict the experimental test results. The confrontation between the experimental and the analytical results are presented and discussed

    Cyclic response of RC beam-column joints reinforced with plain bars: an experimental testing campaign

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    Existing reinforced concrete (RC) buildings constructed until the mid-70’s, with plain reinforcing bars, are expected to behave poorly when subjected to earthquake actions. This paper describes an experimental program designed to investigate the influence of poor detailing on the cyclic behaviour of RC beam-column joint elements. Cyclic tests were performed on five interior and five exterior full-scale beam-column joints with different detailing characteristics and reinforced with plain bars. An additional joint of each type was built with deformed bars for an evaluation of the influence of bond properties on the cyclic response of the structural element. The force-displacement global response, energy dissipation, equivalent damping and damage behaviour of the joints was investigated and the main results are presented and discussed. The experimental results indicate that the bond-slip mechanism has significantly influenced the cyclic response of the beam-column joints. The specimens built with plain bars showed lower energy dissipation, stiffness and equivalent damping

    Nonlinear modeling of the cyclic response of RC columns

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    Cyclic load reversals (like those induced by earthquakes) result in accelerated bond degradation, leading to significant bar slippage. The bond-slip mechanism is reported to be one of the most common causes of damage and even collapse of existing RC structures subjected to earthquake loading. RC structures with plain reinforcing bars, designed and built prior to the enforcement of the modern seismic-oriented design philosophies, are particularly sensitive to bond degradation. However, perfect bond conditions are typically assumed in the numerical analysis of RC structures. This paper describes the numerical modeling of the cyclic response of two RC columns, one built with deformed bars and the other with plain bars and structural detailing similar to that typically adopted in pre-1970s structures. For each column, different modeling strategies to simulate the column response were tested. Models were built using the OpenSees and the SeismoStruct platforms, and calibrated with the available tests results. Within each platform, different types of nonlinear elements were used to represent the columns. Bond-slip effects were included in the OpenSees models resorting to a simple modeling strategy. The models and the parameters adopted are presented and discussed. Comparison is established between the most relevant experimental results and the corresponding results provided by the numerical models. Conclusions are drawn about the capacity of the tested models to simulate the columns response and about the influence of considering or not considering the effects of bars slippage
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