Below is an extract from Vice General Director of Phu My Hung Corporation, Mr. Li Dai Ming’s talk - at a seminar “Foundation solutions for constructions on weak ground” held on March 25, 2005 at Lawrence S. Ting Building. This seminar is organized by MASD, together with supports from Phu My Hung Company and Chau Thoi Concrete 620 Company
Since 1998 up to now, Phu My Hung Joint Venture Company has completed the construction of 13 buildings of all kinds with 9 ~ 13 floors, covering a total area of 164.939 square meter. 16 buildings with 10 ~ 18 floors, covering 289.130 square meter have been under construction. In addition, we have been carrying out the design the project and preparing to construct over 30 buildings with 9 ~ 22 floors of a total area of 702.615 square meter.
With such a high number of constructions, Phu My Hung Joint Venture Company always take a good care of factors relating to the design and construction to make sure that the construction can meet the best quality.
1. Solutions for industrial and civil constructions on weak ground
Building on the ground with thick clay layer shall face two problems: One is the weak load ability due to weak cutting force; the other is the ground sinking because the ground bears a strong pressure. To get the work done quickly, reduce the market price, save the investment capital, we carried out a survey, analyzed, and studied foundation solutions for industrial and civil constructions on weak ground in Shanghai, Tianjin. Guangdong, China, collected related data from Japan, US and Mexico, tried to construct some multi-storey buildings by driving bamboo piles for foundations as previously used in constructions in Vietnam, and to build on floating foundations. The entire foundation solutions with inconsiderable depth as mentioned above could satisfy the load capacity but fail to solve the soil sinking problems, except for foundation piles (with considerable depth) being able to solve both load ability and soil sinking problems. Therefore, Phu My Hung Joint Venture Company mainly uses shaped foundation piles like pre-fabricated concrete rectangular piles 250/250, 300/300, 350/350, 400/400 for house buildings in the developing area of Saigon South City center. Moreover, these piles are produced at factories that are jointly co-operated with Phu My Hung Joint Venture Company. Basically, wooden piles are not used in constructions here, house foundation and columns are built on the parallel top-bottom principle with the floor width of 250~300, except for the Phu My Hung Joint Venture Company’s working office using anti-buoyancy filling piles. To meet the ever-growing construction demands with ever-growing load capacity, we use pre-stressed concrete round piles and filling piles with large diameter for latest buildings, especially the Phu My Hung Joint Venture Company’s head office, which is recognized as Vietnam’s high quality construction.
2. Bridge and Road Traffic Construction
Previously, most road constructions in Vietnam use prefabricated piles. This solution, however, requires a long time to complete, but our constructions are very urgent. In 1996, therefore, we conducted a survey of static bridges that do not open traffic for ships in the area; we found some piles in the river being damaged due to collision. On the other hand, filling pile application solution is used in China for road constructions. Therefore, we tried two solutions from which we found that the prefabricated pile application does not have any advantage. That is why we chose to use the solution of filling piles with diameters of 1200, 1500, 2000 for road constructions. All of the bridges use pre-shaped concrete pre-stressed beams (types 33 m and 24, 54 m) produced by Concrete Company 620. During the construction period, each construction stage is tested and accepted by relevant organizations, especially by Inspection Bureau of the Ministry of Construction (because this is the construction belonging to Group A, involving foreign investment capital). After the whole construction is completed, the Ministry of Construction, MASD, HoChiMinh City Service of Construction and Service of Traffic and Civil Engineering also jointly conducted an inspection to accept, in which there were three steel pipe bridges being recognized as Vietnam’s high quality constructions (Ong Lon Bridge, Xom Cui Bridge and Can Giuoc Bridge)
3. Foundation Construction Method
For double basement constructions like Phu My Hung Joint Venture Company’s head office with its depth of -11,0m, we use a protection method of supporting wall and concrete brace when digging ground for basements. This supporting wall shall help the structure protect the basements for a long time. After treating the supporting wall surface technically, it shall concrete more reinforced concrete walls with 200 thick next to the supporting wall, and perform waterproof treatment in combination with drainage. This solution has gained some good results. For constructions with one basement or half basement, simple protection method is applied in digging grounds, creating a slope and a partial brace, using the applications of outside waterproof and waterproof self-structure for basement. In addition, this solution has gained some good results. Construction floors are not directly built on weak ground but on reinforced concrete hollow floor to avoid floor sinking. On the other hand, to avoid sinking at ancillary work surrounding the main constructions, we use a sinking gap to separate the constructions and enhance the safety treatment timely. For road constructions, we use a sinking anticipation method for roadbeds. At the beginning, temporary road surface is constructed. After the roadbed reaches a stable sinking, the main roadbed shall be constructed.
4. Applied By-laws
We apply by-laws of Europe, U.S., Taiwan and China. However, it is acceptable for any by-law that meets the Vietnam by-law. Generally, multi-storey buildings apply Vietnam by-law; and tall buildings apply US and Japan by-laws.
To put the concept of advanced design into use, we invited about 10 designers from US, Japan, Germany, Thailand, Taiwan and China to design the construction project, and also invited two design companies like SPCC and NQH, both having practice license in Vietnam to complete the drawing of structure and detailed construction work. These two companies have enough architects and foreign engineers with high qualifications to assist in establishing the construction design drawing. We also put into use of the solutions to divide the traffic for vehicles and walkers, and separate the green area and resting area at large-scale areas; design a large-scale space without beams and columns in order to expand and separate the space at one’s discretion; design steel pipe composition coupled with concrete.
6. Calling for and Inviting bid for construction work
We comply with Vietnam law, taking priority in choosing highly eligible construction companies, to carry out calling for bid in a public, fair and carefree way.
7. Construction work Management
We hire a professional consulting company with experience to manage and supervise the entire housing construction work, except for the infrastructure work by Phu My Hung Joint Venture Company’s Construction work department.
8. Construction contract management
We always maintain our trust with the government, with customers, build up a good relationship with construction companies, suppliers on the fair and prestigious basic. Among thousands of signed contracts, we have not owed any designers, construction companies and suppliers, strictly complied with FIDIC terms, as well as International trading regulations.
9. Construction quality management
Maintaining the development of product quality, providing customers with good quality products, creating prestige among customers. Carrying out the construction works according to the project, supervising, testing and checking subject to by-laws, making sure of the house quality that we use. During the construction process, we apply quite many effective controlling methods like focusing on one location to mix concrete and process steel rods; Phu My Hung Company shall purchase other important materials for the construction companies. It is because of strict supervision and because investor directly supplies important materials to the construction sites, together with the investor’s supervision and consulting supervisors. That is why all of construction works are finished subject to the schedule, quality, design, providing secured quality for housing construction work in general, and tall buildings on weak grounds in particular. This is also Phu My Hung Joint Venture Company’s life-or-death aim.
10. Construction work Safety Management
We require that our construction companies should establish labor safety methods, positioning professional staff to check regularly. Every month, investor and supervising company shall organize an entire check to evaluate for appraisal, to prepare well enough work safety methods to make sure of the labor safety.
11. Environment Management
Carrying out the close management of construction work, we set up some regulations about civilized work execution management, which is tested monthly in order to evaluate for appraisal.
12. Construction Work Technique
We applying the technique to prevent the soil from falling when digging deep foundation on weak ground at high speed, large size formwork set-up technique, high function and intensity concrete technique, apply popularly high tensile steel, large diameter steel connecting technique, apply new formwork and truss technique, amorphous pre-stressed construction technique … In addition, we put into use of oxidized waste water treatment technique.
13. Materials and Equipment
High-class doors and windows, high-class sanitary accessories, high-voltage electrical alloy, high-class wall and floor tiles are put into use. We also apply automatic pile joint machine with high load and its technical work; and we are applying reinforcement mat frame technique, pre-stressed round concrete pile…
14. Accepting the construction work
During the work execution process, we invite some engineers from a supervising company to carry out a direct supervision on site to check the overlapping construction, individual parts, items, or check briefly the construction work completion. After the brief checking has been passed, the investor, supervising company and Construction Company shall carry out the acceptance. If the checking is satisfied, the relevant state organizations shall be invited to carry out the work acceptance and completion. The entire construction shall only be taken over if the acceptance is satisfied.
Above are the achievements that Phu My Hung Joint Venture Company has made and brought some good results from the beginning, especially for tall buildings on weak ground in the South of HoChiMinh City. We hope that our practical experience could be a source of reference for the city and other companies. With a good care from our leaders of different levels and sectors, we believe that we shall make more efforts to build Saigon Southern City more quickly with better quality and more investment effective with a hope of working with HoChiMinh City to build more tall building blocks with high quality to give local residents more beautiful houses, as well as to give them a chance to enjoy the best things that we can make in order to increase the housing fund of the city and meet the ever growing demand of residence community.