Fire resistance optimization design method of reinforced concrete two-way partition floor in subway depot

Abstract

The invention provides a fire-resistant optimized design method for a reinforced concrete bidirectional compartment floor between a metro depot and a superstructure. The fire-resistant optimized design method comprises the following steps of establishing a numerical model of the floor according to four-sided clamped conditions through adopting a finite element method firstly, dividing finite element grids, calculating and drawing a deflection-time curve after burning and finding out inflection points of curvature on the curve; determining the distribution of plastic hinge lines at the inflection points and the node rotation amount of a hinge outlet section by adopting a subdivision node search method; calculating the thin film force and the section resistance at the plastic hinge lines through the plastic hinge rotation amount according to the material performance of concrete and rebars at corresponding temperature, and determining the corresponding residual bearing force of a burned plate; calculating the fire-resistant time and the residual bearing force of the burned reinforced concrete bidirectional plate, and carrying out optimized design. According to the fire-resistant optimized design method provided by the invention, the actual fire-resistant time and the residual bearing force after burning of the reinforced concrete bidirectional compartment floor can be accurately predicted, the construction cost increased for 3-hour fire-resistant duration time can be reduced, and the purpose of reducing the cost is achieved.

Description

technical field [0001] The invention relates to the field of fire protection, especially to the fire protection design of buildings, and in particular to a reinforced concrete two-way partition floor slab for the superstructure of a subway car depot Fire resistance optimization design method. Background technique [0002] In recent years, domestic subway construction has entered a stage of rapid development. In order to make full use of urban soil resources, subway construction units usually develop the building industry above the subway depot. Specifically, it is to build a large reinforced concrete partition floor on the upper part of the management center building where the subway trains are parked for structural type conversion, and to build a civil building on the top of the conversion floor as a commercial residence for sale. [0003] In order to ensure that the superstructure has sufficient safety in the event of a fire, the reinforced concrete partition floor must m...

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Problems solved by technology

The increased construction cost of these engineering measures is often as high as tens of millions of yuan.

In fact, for reinforced concrete two-way partition slabs, the surrounding consolidation constraints will have a significant beneficial effect on effectively prolonging the fire resistance time of the slab, and at the same time, the membrane effect of the slab surface can also effectively prolong the fire resistance of the slab However, in the actual design of the fire resistance performance of reinforced concrete two-way slabs, these two beneficial effects are usually conservatively ignored, and the design fire resistance time of this split slab is shortened

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