Concrete-filled steel tubes offer superior fire resistance and fire protection for steel pipes. When steel pipes are filled with concrete, they can absorb a significant amount of heat energy during a fire. As a result, the temperature distribution across the cross-section of the pipe becomes uneven, which extends the fire-resistance time of the columns and slows down the heating rate of the steel. Once the steel column begins to yield, the surrounding concrete can carry most of the axial load, preventing structural collapse. Additionally, the fire resistance of composite beams is enhanced because the heat from the top flange of the steel beam is transferred into the concrete, lowering the overall temperature of the steel.
Experimental data indicates that using fire-retardant coatings can save between 1/3 to 2/3 or even more in fire protection time compared to traditional steel columns when maintaining first-class fire resistance for three hours. Moreover, as the diameter of the steel pipe increases, the amount of coating required decreases significantly.
In terms of corrosion resistance, concrete-filled steel tubes perform better than conventional steel-concrete structures. The exposed surface area of the steel tube is greatly reduced, minimizing the contact with corrosive gases from the environment. This leads to lower maintenance costs and improved durability compared to standard steel structures.
The cross-sectional shape of concrete-filled steel tubular members has a significant impact on the performance, construction efficiency, and cost of steel-concrete structures. Round steel tubes effectively confine the internal concrete, placing it under triaxial compression, which enhances its compressive strength. However, constructing round steel tube structures can be challenging and expensive. On the other hand, square steel tubes are easier to construct and more cost-effective, although the confinement effect on the concrete is less, resulting in lower load-bearing capacity. Therefore, the choice of cross-section depends on the specific requirements of the project, balancing performance, cost, and construction feasibility.
The rechargeable fan is a portable device. It is usually composed of plastic parts such as a shell, batteries, circuit control boards, DC motors, lamps, and cables. It is easy to carry and use. It is suitable for outdoor cooling, vehicle and ship carrying, camping, power failure emergency, temporary operations and other occasions without power supply .
Rechargeable fan features include:
1. Portability : small size, easy to carry and use 2.
2. Versatility : usually equipped with lighting, USB charging interface, support computer, charging bank and other power supply modes .
3. Energy saving and environmental protection : the use of advanced energy-saving circuit design, long time will not consume electricity .
4. Safe and reliable : with battery overcharge and discharge protection, extend battery life .
5. Wide application scenario : suitable for home, office, outdoor and other environment .
Rechargeable Fans,Household Pedestal Fan,Household Floor-standing Fan
Guangdong Dp Co., Ltd. , https://www.dp-light.com