What's new in the "Standard for Design of Roof Structure Snow Load"

  Recently, a video conference on the review of the China Construction Standardization Association Standard "Design Standard for Snow Load on Roof Structures (Draft)" edited by Jianyan Technology Co., Ltd. was successfully held. After listening to the preparation team's report on the standard preparation process and content, the review expert group reviewed the standard contents one by one. After thorough discussion, the reviewing expert group believes that the preparation group, based on the research and analysis of relevant domestic and foreign standards and norms, aimed at the snow distribution coefficient of the typical structure, the basic snow pressure statistical distribution characteristics, the quantitative definition of the snow load sensitive structure and the local snow load, etc. Problems, carried out a lot of investigation and research and test verification. The technical content of the standard submission for review is scientific and reasonable, and it is strong in operability. It is an important supplement to the national standard "Code for Loads of Building Structures" and fills the gap in the special standards for snow load in China. It has reached the international advanced level in general, and the standard has passed the review.

    "Snow Load Design Standards for Roof Structures (Draft for Review)" is divided into 6 chapters and 3 appendices. The core content and calculation system framework follow the provisions of the national standard "Building Structure Load Code" GB50009-2012, but there are several aspects Expanded and refined.

Local snow load

1. Snow load near roof protrusions

2. Hanging snow and ice load at the cantilevered edge of the roof

3. Lateral force of the snow block

2. The snow distribution coefficient of the spherical roof is proposed

The standard also refines the snow cover distribution coefficients for single-span double-slope roofs and low roofs connected to higher buildings.

3. The snow distribution coefficient introduces the adjustment coefficient

  This coefficient is called "exposure coefficient" in foreign standards. The exposure coefficient is generally 1.0, and when there is more shielding around the surrounding area (resulting in a snow-free roof area), it is greater than 1.0, while the opener coefficient is less than 1.0.

4. Supplement the basic snow pressure values of some county-level cities across the country

According to the data of the National Meteorological Center and the basic snow pressure contour map of the load code, the standard analyzes and organizes the basic snow pressure in some county-level cities across the country to facilitate the use of structural personnel.

5. Clarified the definition of "snow load sensitive structure"

What is snow sensitivity is a problem that has always plagued designers. This is explained in the description of the "Load Code". The standard further quantifies this interpretation and uses the "ratio of the standard value of snow load and the standard value of the self-weight load of the roof" as the basis for judgment. It is convenient to judge the sensitive structure of snow load.

6. Appendix A of this standard introduces "Special Research on Snow Loads"

  Domestic long-span roofs are increasing, their shapes are becoming more and more complex, and their spans are becoming larger and larger. Many roofs have exceeded the scope of the standard regulations. In order to ensure structural safety, special research should be carried out.

  The relevant provisions of the "Snow Load Design Standards for Roof Structures" draw on the relevant provisions of foreign standards to supplement and improve the provisions of the roof structure snow loads in the load codes, which enhances the scientific and reasonable value of snow load values in China. The value level is closer to the international advanced level.

  This article is reproduced from: CABR Engineering Consulting Design Institute