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Seismic behavior of frost-damaged squat RC shear walls under artificial climate environment: a further experimental research

Rong Xian-Liang, Zheng Shan-Suo, Zhang Yi-Xin, Dong Li-Guo, Liu Huan, Dai Kuang-Yu

Archives of Civil and Mechanical Engineering

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2020

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Vol. 20, no. 4

103--124

EN

In cold environment, the damage of freezing and thawing poses a great threat to the safety of concrete structures. In this study, six frost-damaged squat reinforced concrete (RC) shear walls were subjected to low cyclic reversal loading to investigate the effects of axial compression ratio, concrete strength and freeze-thaw cycles (FTCs) on the seismic performance of squat RC shear walls. The seismic behavior of the test specimens was evaluated in terms of the frost action at the microstructure level, frost-heave crack patterns, damage processes, failure patterns, hysteretic behaviors, skeleton curves, deformations, and energy dissipation capacities. It shows that the boundary elements and distributed reinforcements had obvious restraining effects on the development of frost-heave cracks. The FTC action weakened the load-carrying capacity, energy dissipation capacity, and shear resistance capacity of the walls. When the number of FTCs is kept at 200, with the increase of the concrete strength, the gel structure (C-S-H) gradually evolved from fibrous to nets, also the width and number of frost-heave cracks started to reduce, and the distribution of frost-heave cracks evolved from the middle of the specimen to the perimeter. Moreover, the energy dissipation capacity and the ratio of the shear displacement on the whole displacement after cracking loading condition started to increase.

2

Problematyka utrzymania nawierzchni wodoprzepuszczalnej w klimacie chłodnym

Suchocka M., Magdziak M.

Drogownictwo

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2018

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nr 7-8

216--222

PL

Idea równoważonej gospodarki wodnej jest częścią ogólnej koncepcji zrównoważonego rozwoju. Niedobór wody w środowisku zurbanizowanym wywiera negatywny wpływ na funkcjonowanie ekosystemu miasta. Z kolei nadmiar wody objawiający się występowaniem podtopień lub powodzi może wyrządzić wiele szkód. Zarządzanie wodą na terenach zurbanizowanych jest dużym wyzwaniem w obecnych czasach, szczególnie po zmianie Ustawy Prawo wodne. Stosowanie nawierzchni o charakterze wodoprzepuszczalnym na terenach miejskich stanowi jedną z dobrych praktyk w zrównoważonym gospodarowaniu zasobami wodnymi. W czasach wzmożonej troski o zasoby wodne i ich jakość należy dążyć do sytuacji, kiedy woda pozostaje tam, gdzie spadła wraz z deszczem. Skuteczną realizację tego celu można uzyskać rozszczelniając obecne nieprzepuszczalne powierzchnie miejskie, w zamian stosując nawierzchnie wodoprzepuszczalne. Rozwiązanie to ma ogromny, niewykorzystany potencjał, ponadto nie generuje dodatkowych kosztów ani trudności w zastosowaniu, pomimo powszechnie panujących poglądów. W artykule zaprezentowano analizy przeprowadzonych badań w Durham, w trudniejszym niż w warunkach Polski klimacie, dotyczące zastosowania nawierzchni wodoprzepuszczalnych. Ich wyniki wskazują, że nawierzchnie przepuszczalne i porowate funkcjonują tam poprawnie i spełniają swoje zadania. Stąd wniosek, że w warunkach polskich mają one szansę zastosowania z takim samym powodzeniem.

EN

The idea of water management is part of the overall concept of sustainable development. The lack of water in the urbanized environment has a negative impact on the city’s ecosystem. On another hand, the water can cause the occurrence of flooding and a lot of damage. Water management in urbanized areas is an important challenge nowadays, especially after the amendment of the Water Law Act. The use of a water-permeable surface in urban areas is one of the good practices in the sustainable management of water resources. In times of increased care for water resources and their quality, we should aim for a situation where water stays where it fell with rain. The effective implementation of this objective can be achieved by using instead the impermeable urban surfaces, the water-permeable surfaces. This solution has a huge, untapped potential, moreover, it does not generate additional costs or difficulties in the application, despite common opinions. The paper presents analyses of the research conducted in Durham, in a climate more difficult than that of Poland, concerning the use of water-permeable pavements. The results show that permeable and porous pavement function properly and perform their tasks. Therefore, it is concluded that in Polish conditions they have a chance to be used with the same success.

3

Ship-to-ship operations in cold climate environments

Berg T. E.

TransNav : International Journal on Marine Navigation and Safety of Sea Transportation

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2007

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Vol. 1, no. 3

327--332

EN

Within the Norwegian maritime cluster there is a growing interest in studies of harsh weather marine operations. For the oil industry offshore loading is a preferred operation for production at minor oilfields far from existing infrastructure. Safe and cost-effective production from recent oil and gas discoveries close to the coastline of Northern Norway introduces new challenges due to cold climate environments. At the same time increased transit of oil from northwest Russia will require increased ship-toship transfer in an optimized cargo chain from the oilfields to customers in Europe and the USA.

4

Computer Usage With Cold Hands; An Experiment With Pointing Devices

Blomkvist A. C., Gard G.

International Journal of Occupational Safety and Ergonomics

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2000

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Vol. 6, No. 4

429--450

EN

Computers are used in the outdoors and in connection with cold store work. Cold hand and fingers limit data input, as studied here. Six input devices; trackballs, pens, and a mouse were tested by 19 participants in a Fitts' target acquisition task with 2 target sizes under 2 experimental conditions; warm and cold right hand. Measures were acquisition times, number of errors, participant's preferences, and observed handling of the devices. Effects of device, target size, and cold were significant. Learning and attempts to improve handgrip were confirmed. Large enough targets, a thick pen, and a mouse make computer work practicable in the cold. Direct visual feedback, as with pen on template with target images, shortened acquisition times by half a second.