Economic Spacing of a Roof Truss

The economic spacing of a roof truss refers to the optimal distance between two trusses to achieve the most cost-effective design. This spacing is calculated based on several factors, including the cost of purlins and roof covering.

Factors Affecting Economic Spacing

1. Cost of Purlins: Purlins are horizontal members that support the roof covering and transfer the load to the trusses. The cost of purlins depends on their size, material, and spacing. The larger the purlins, the more expensive they will be. Therefore, increasing the spacing between trusses can reduce the number of purlins required and lower the overall cost.

2. Cost of Roof Covering: The cost of the roof covering is another factor that affects the economic spacing of a roof truss. The type of roof covering used, such as tiles, shingles, or metal sheets, will determine the cost per square meter. Increasing the spacing between trusses can reduce the overall area of the roof, thereby reducing the cost of the roof covering.

3. Dead Loads: Dead loads refer to the weight of the roof structure itself, including the trusses, purlins, and roof covering. The spacing of the trusses must be designed to support these dead loads without overloading the structure.

4. Live Loads: Live loads refer to the weight of people, equipment, and other objects that may be placed on the roof. The spacing of the trusses must also be designed to support these live loads without overloading the structure.

Conclusion

In conclusion, the economic spacing of a roof truss depends on the cost of purlins and roof covering. By increasing the spacing between trusses, the number of purlins required and the overall area of the roof can be reduced, resulting in a more cost-effective design. However, the spacing must be designed to support both the dead and live loads without overloading the structure.

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