Author丨Du Xinjie
Unit丨China Construction Fifth Bureau Steel Structure Company
Metal plates are lightweight, high strength and high toughness compared to concrete plates. Therefore, metal roof can realize some newer architectural forms, and are mostly used in the enclosure construction of modern venues such as art museums and airport high-speed rail stations. At present, there are few cases of large antique buildings using metal roofs in China. I will share the ideas of design, , node design and large slope roof construction for metal roofs in an antique building project. I hope everyone likes it.
Project Introduction and Design Background
Project Introduction: This case originated from the Yellow River Intangible Cultural Heritage Project. The project is located at the junction of Gucheng Road and Longmen Avenue in Luoyang City, Henan Province. It is a key project in the province and a key city people's livelihood project. The total roof area of this project is about 36,000 square meters, and the roof waterproof level is the first-level, including three parts: the roof of the intangible cultural heritage exhibition hall, the intangible cultural heritage book city, and the intangible cultural heritage academic exchange center. The roof structure adopts a multi-layered continuous slope roof form, which makes the overall shape of the roof ups and downs, symbolizing the endless flow of the Yellow River and the long-lasting Yellow River culture. The roof of this project has the characteristics of super-large slope, overall connection, and double-layer rafter eaves antique.
Picture 1 Project roof renderings
Design background: The roof construction plan of this project was made by Professor Li Li's team of Tongji University Design Institute, and the construction drawings were designed by China Automobile Industry Engineering Co., Ltd. . Professor Li Li's team enjoys a high reputation in Luoyang . Most of the local public venue buildings adopt Professor Li's design plan, which is deeply trusted by the owners. Our Steel Structure Design Institute of the Fifth Bureau is conducting a second deepening of the construction drawings to ensure that the original design plan can be implemented perfectly. How can we achieve the roofing target effect in the plan? Let me take you into the process of preliminary plan design.
Roofing Plan Design
▍1-Enterprise
Tender List Plan Analysis, Showing Professional and Technical Strong.
Initially, after confirming the winning bid. Regarding the description of the bidding list, after analysis by our designers, this roofing plan cannot meet the appearance design of the building, and there are also cost waste, and there are serious water leakage risks. Therefore, although this solution is low in cost, it does not have application value. Therefore, we judge that the roofing practices of the project are likely to be major changes.
Figure 2 Analysis of bidding list plan
▍2-Crazy
Construction effect conflict, and the plan stage is in a quagmire.
After the unnecessary cost item in the removal plan, the work of completing the waterproof performance of the roof was completed, and the first upgrade of our roof plan was completed. However, it still cannot achieve the architectural effect that Tongji University Design Institute wants. Tongjiyuan was very disappointed with this plan and then provided a roofing structure method on its own. However, after market research, the unit price of this plan is about 2,500 yuan/㎡. The owner needs to add about 70 million yuan to the individual items of the metal roof, which is several times our bid price. Therefore, the owner also felt hesitant, unwilling to increase too much investment and unable to deny Professor Li's work on closure, so he was unable to make a decision. The project has fallen into a stagnation phase.
Figure 3 Comparison of the design plans of Tongji Academy and China Automobile Academy
▍3-Break the deadlock
Analyze the conflict points between the two sides and find the best solutions to seek win-win results.
After Tongjiyuan provided the solution, our designers carefully analyzed the proposed solution and we came up with two reasons for the higher cost: First, the system itself must use a insulation material and its adhesive imported from abroad, which is a monopoly product in China and has a very high price; Second, the roof uses "metal and tiles" as the decorative layer to achieve antique effect, which is relatively high.
Taking cost as a breakthrough, we optimized the plan proposed by Tongjiyuan.But considering the building's exterior requirements, we made the decision to retain "and tiles" as the outermost decorative tiles. At the same time, the wind-resistant clip and keel are designed to provide a fixed structure for the tile. The lower layer structure consists of aluminum, magnesium, manganese metal plates and TPO waterproof coils. The main insulation layer is the insulation layer, supplemented by gas insulation layer, steam permeability layer, force-sustaining layer, etc. The entire roof has a total of 12 layers.
The number of structural layers and materials of the new solution are twice that of the original solution, but the price is still only 1/2 of the original solution. Therefore, the plan proposed by our company is very recognized by the owners. At the same time, the aluminum, magnesium, manganese materials, tiles and other materials used in this plan are also the materials in the plans of the Institute of Automobile and Tongji Institute respectively, so the two design institutes have no objection.
Roof construction structure plan has been successfully implemented with the common recognition of all parties. This is the first time that Hewa has been used in hard roofs such as non-concrete slabs, and it is also the first time that Hewa has been used in large-area roofs.
Figure 4 Final roofing plan
Project implementation effect and summary
Figure 5 Aerial photography on the south side of the book city
Figure 6 Aerial photography on the east side of the exhibition hall
After the plan is optimized, the roof was carried out smoothly during the formal construction, and the construction was finally completed with a saving of 20% of the construction period.
Reviewing the design process of this project, we can see that professional design capabilities play an important supporting and leading role in the project. Only with strong technical strength can a professional company design institute move from the back end to the front end; only a design plan that is sufficiently in line with the industry and the market can win the recognition of the owners, design institutes, and construction units, truly control the direction of the project, and help the project perform its contract with high quality!
