1, the plot ratio is 2, and the mass ratio is 3. This problem is more complicated. The state explicitly prohibits subcontracting. Big package refers to general contracting, cleaning package refers to cleaning work, and subcontracting generally refers to professional subcontracting into doors and windows, water and electricity, etc. Subcontracting refers to transferring the contracted project to other units for construction. 4. Critical strength generally refers to the strength of the material when it is close to failure. 5. Water supply (up and down), power supply, access, postal service, communication, etc. Also known as "building control line", it refers to the boundary line that controls buildings or structures (such as external walls and steps) along the street on both sides of urban roads facing the street in urban planning and management.
Any street building or structure shall not exceed the property line. The building red line consists of the road red line and the building control line.
The road red line is the planning control line of urban roads (including residential roads); Building control line is the control line of building basement position. On the side of the base adjacent to the road, the red line of the road is generally used as the building control line. For example, due to the needs of urban planning, the competent department can set up a building control line outside the road route, which is generally called the red line construction of the back road.
No building shall exceed a given property line. 7. The construction permit shall be handled by the construction unit (Party A) to the construction administrative department. 8. The warranty period of construction products shall be stipulated by the state, and the basic engineering and main structure engineering shall be the reasonable service life of the project specified in the design documents; Roofing waterproof project, leakage prevention of toilets, rooms and external walls with waterproof requirements, five years; The heating and cooling system consists of two heating periods and cooling periods; Electrical piping, water supply and drainage piping and equipment installation for 2 years; The renovation project will last for 2 years.
The warranty period of other projects shall be agreed by the construction unit and the construction unit. The warranty period of housing construction project is calculated from the date when the project is completed and accepted.
9. Super enterprise: it can undertake the construction of various housing construction projects. First-class enterprise: it can undertake the following housing construction projects with a single construction and installation contract amount not exceeding 5 times of the registered capital of the enterprise: (1) housing construction projects with 40 floors and below and various spans; (2) Structures with a height of 240 meters or less; (3) Residential quarters or buildings with a building area of 200,000 square meters or less.
Second-class enterprise: it can undertake the following housing construction projects with a single construction and installation contract amount not exceeding 5 times of the registered capital of the enterprise: (1) housing construction projects with 28 floors and below and a single span of 36 meters and below; (2) Structures with a height of120m or less; (3) Residential quarters or buildings with a building area of 6.5438+0.2 million square meters or less. Grade III enterprise: can undertake the construction of the following housing construction projects with a single construction and installation contract amount not exceeding 5 times of the registered capital of the enterprise: (1) 14 floors and below, and housing construction projects with a single span of 24 meters and below; (2) Structures with a height of 70 meters or less; (3) For residential quarters or buildings with a building area of 60,000 square meters or less, 10, the subcontracting of projects and services must be signed with the general contractor.
2. Some basic questions about housing construction (only simple answers)
1. The first to third floors are low-rise residential buildings, the fourth to sixth floors are multi-storey residential buildings, the seventh to ninth floors are medium-high-rise residential buildings, and the tenth and above floors are high-rise residential buildings.
2.3 Basic Provisions 3.0. 1 Residential design should meet the requirements of urban planning and residential area planning, and use land and space economically, reasonably and effectively. 3.0.2 Residential design should coordinate the building with the surrounding environment and create a convenient, comfortable and beautiful living space.
3.0.3 Residential design should be people-oriented, and meet the use requirements of special groups such as the elderly and the disabled in addition to the general living requirements. 3.0.4 Residential design shall meet the requirements of sunshine, natural lighting, ventilation and sound insulation required by residents.
3.0.5 Residential design must meet the requirements of energy conservation, and residential buildings should be able to make rational use of energy. According to the local energy conditions, the energy supply mode combining conventional energy and renewable energy should be adopted.
3.0.6 Residential design should be standardized, modular and diversified, actively adopt new technologies, new materials and new products, and actively promote industrialized design, construction technology and modular application technology. 3.0.7 The structural design of the residence shall meet the requirements of safety, applicability and durability.
3.0.8 The residential design shall comply with the provisions of relevant fire protection codes and meet the requirements of safe evacuation. 3.0.9 The residential design should meet the basic requirements of effective function, safe operation and convenient maintenance of the equipment system, and reserve a reasonable installation location for related equipment.
3.0. 10 residential design should not only meet the requirements of recent use, but also consider the possibility of future transformation. 3. Building density (building density; Building coverage), [1] refers to the ratio (%) of the total basement area to the occupied area of a building within a certain range.
Refers to the coverage rate of buildings, specifically refers to the ratio (%) of the total basement area of all buildings in the project land area to the planned construction land area, which can reflect the vacant land rate and building density in a certain land area. 4. The plot ratio refers to the ratio of the total construction area of residential areas to the land area.
For developers, the plot ratio determines the proportion of land cost in housing, while for residents, the plot ratio is directly related to the comfort of living. In a good residential area, the plot ratio of high-rise residential buildings should not exceed 5, that of multi-storey residential buildings should not exceed 2, and that of green space should not be less than 30%.
However, due to the limitation of land cost, not all projects can be done. 5. Also called "building coefficient", or "K" value, refers to the percentage of building area (living area in residential buildings) in the building area.
The calculation formula is: building plane coefficient = usable area/building area * 100%. The plane coefficient of building is one of the technical and economic indexes of building. Used to measure the economic rationality of plane layout. For example, in residential buildings, the plane coefficient of buildings is generally 50-55%.
In the case of the same residential building area, increasing the K value can increase the living area. When the value of k increases 1%, if the unit cost of construction area remains unchanged, the investment can be reduced by 1.4% according to the average living area. 6. The positioning axis should coincide with the main grid axis.
Distance between positioning lines (such as span, column spacing, height, etc.). ) shall conform to the module size to determine the position and elevation of the structure or member. The connection between structural members and plane positioning lines should be conducive to the unification and interchange of horizontal members, beams, slabs, roof trusses, vertical members, walls and columns, and make the structural members bear reasonable forces and simplify the structure.
7. Refer to the corresponding building codes and general design modules. 8. Use space and equipment space.
9. Standard single bed1900 * 900; Double bed 2000 *1500,2200 *180010. According to the code for residential design, when the height of the window sill of 3.9. 1 is less than 0.90m from the floor and ground, there should be protective facilities and a balcony or platform outside the window. The clear height of the window sill or the height of the protective railing should be calculated from the treadable surface to ensure that the clear height is 0.90 meters.
The stairwell design of11.80cm12.4.1shall comply with the current national standards, Code for Fire Protection Design of Buildings (GBJ 16) and Code for Fire Protection Design of High-rise Civil Buildings (GB50045). 4. 1.2 The clear width of the stair section should not be less than 1. 10m.
For residential buildings with six floors or less, the width of stairs with railings on one side should not be less than1m. 13. There are many atlases in various places, including the building materials and practices of a roofing waterproof project 1. Cast-in-place reinforced concrete slab II. 1:6 cement slag slope is 2%, and the lowest part is 30mm thick.
3.20㎜ thick 1:3 cement mortar leveling. 4.2 mm thick polyurethane waterproof material.
5. 1.5㎜ thick EPDM waterproofing membrane. 6.30 thick polystyrene extruded insulation board.
7.3㎜ thick hemp knife ash isolation layer. 8. Color cement brick shall be paved with 25-thick 1:3 cement mortar, with a joint width of 3㎜, and sand shall be filled for cleaning.
14. Concrete slope and mortar slope, with concrete slope as the main slope. 15. It shall be calculated and determined according to Article 4.9 of Code for Design of Water Supply and Drainage in Buildings (GB500 15-2003).
16. Flooding is a kind of building waterproof technology. Generally speaking, it is actually the waterproof treatment of the intersection between the wall and the roof, that is, all the plane facades that need waterproof treatment. To put it bluntly, it is to wrap the corner with waterproof material. Unlike aproll.
17. Organized and unorganized drainage. 18. This is a bit much, but it's almost the same. The wall materials are different. 19. Reinforced concrete frame structure, shear wall structure, frame shear wall structure, frame tube structure and tube structure, brick-concrete structure and brick-concrete structure.
20. Corridor combination, suite combination, hall combination, unit combination and comprehensive combination. 2 1. The stair tread width should not be less than 0.26m, and the tread height should not be greater than 0.175m. ..
22. The gap between the stair railing uprights should not be greater than 0.11m.. 23. When the length of the railing in the horizontal section of stairs is more than 0.50m, the height of the handrail should not be less than1.05 m.
24. The protective layer paved with masonry or concrete around buildings such as houses is more than one meter wide [2]. The purpose of setting apron is to drain the groundwater near the footstool of the external wall of the building quickly, prevent the eaves from dripping and washing the soil around the external wall, reduce the possibility of the wall and foundation being soaked by water, protect the wall and foundation and prolong the service life of the building.
25. Prevent the moisture in the soil from rising along the foundation wall, prevent the groundwater at the foot of the slope from infiltrating into the wall, and make the wall damp. The horizontal moistureproof layer should generally be within the range of indoor impervious cushion (such as concrete), usually set at an elevation of 0.006m, and at least 0/50 mm higher than the terrace outside the city to prevent rainwater from splashing on the wall.
When the ground is a permeable material (e.g.
3. Seek the details of common sense of construction safety (100, and add 100 after adoption).
Safety accidents are as fierce as tigers. The collapse of a building in a residential area in our city last month has left us with lingering fears.
The occurrence of construction accidents is largely due to the lack of awareness and knowledge of construction safety of construction workers. Sometimes, a small negligence may cause serious accidents, and we must not take it lightly.
In this special issue, some construction safety knowledge is published for readers to learn and understand. In building construction, there are many aerial work.
The so-called aerial work refers to any work that may fall at a height of more than 2m (including 2m) from the reference plane of falling height, which is called aerial work. Because of the small activity area, much air around, strong wind and many vertical cross operations, aerial work is a very complicated and dangerous work, and a slight negligence will cause serious accidents.
Working at heights must strictly implement the safety technical specifications for working at heights in construction. I. Types and causes of accidents at heights 1. Workers working at heights lack proper safety technical knowledge and self-protection awareness.
2. The safety protection facilities and equipment for working at heights are not perfect. 3. The material strength of the trampled object is not enough.
When the aerial work moves, it is empty, slippery and unstable. 5. Do not take protective measures in accordance with the provisions when the three-dimensional vertical cross operation.
6. When working high above the ground, people fall due to collision, electric shock, wind and other reasons. Second, work at heights must strictly abide by safety regulations. Workers working at heights should wear tight overalls, non-slip shoes, safety helmets and safety belts.
2. In case of heavy fog, heavy rain and gale of magnitude 6 or above, it is forbidden to work at heights. 3. Tools not used for working at heights should be put into tool bags and carried as needed.
Commonly used tools should be tied to the body, and unnecessary tools and removed materials should be slid to the ground with a tether, and cannot be thrown down to avoid falling and hurting people. After the operation, it should be cleaned up in time and transported to the designated place to prevent falling and hurting people.
Third, the safe operation specification of crossover operation The aerial work at different levels (heights) in the construction site space at the same time is called crossover operation. Its safety operation specification is: 1. Operators are not allowed to work on the same vertical plane when exchanging up and down.
The lower working position must be outside the range where the upper working object may fall; When it cannot be met, an isolation protective layer should be set between the upper and lower parts. When the height of high-rise building exceeds 24m, cross operation shall be carried out.
Double protection facilities should be set up. 2. It is forbidden for lower-level workers to rest under protective railings and platforms.
Four. The safety operation specification of climbing operation on the construction site, with the help of climbing appliances or facilities, is called climbing operation. Its safety operation specification is: 1. Operators should go up and down the designated passages, and climbing and jumping on non-designated passages such as balconies are not allowed.
2. When going up and down the ladder, be sure to face the ladder, hold hands tightly, and don't climb with objects in your hands. 3. It is forbidden to work on balcony railings, steel bars and pipe racks, templates and their supporting rods.
4. It is forbidden to walk and work along the roof truss winding, purlin and unfixed objects. 5. Personnel should take a special passage to get up and down the scaffold, and it is forbidden to climb up and down the scaffold bar.
When working or walking on scaffolding, pay attention to the probe board under your feet. V. Protective measures for aerial work 1. Protective railings of 1- 1.2m should be set around the aerial work platform, and the railings should be closed with dense mesh safety nets.
Around the bottom, 18cm advanced treadboards are laid, and the platform board is 5cm thick wooden scaffolding. The platform is equipped with ladders for staff to get on and off. The ladder shall be firmly fixed with the platform skeleton, and the pedal spacing shall be 30cm.
2. Protection of limb operation When working at heights, when there is no fence at the edge of the working face or there is a fence, but the height is less than 0.8m, this kind of limb operation is limb operation. Balcony, floor, roof, foundation pit and other adjacent edges should be erected with protective railings, and the external federated eye network should be closed.
When the inner scaffold is used to build a wall, the outer side of the scaffold is closed with a federated eye network; The gap between the inside and the wall should also be closed to prevent people from falling. 3. In the process of construction, there are various potholes, which have certain security risks.
According to the different sizes and positions of holes and holes and the requirements of construction scheme, the holes should be tightly closed. If it needs to be dismantled, it must be approved by the person in charge of the site.
Six, building trauma rescue knowledge 1. Treatment of open wound ① Cleaning and disinfecting the wound. Use normal saline and alcohol cotton balls to clean up the silt and dirt on the wound and the surrounding skin, use clean gauze to absorb the water and oozing blood, and then use alcohol and other drugs for preliminary disinfection. In the absence of disinfection conditions, you can wash the wound with clean water, preferably with tap water, and then dry the wound with a clean cloth or dressing.
(2) Hemostasis, for bleeding wounds, whether it can stop bleeding in time and effectively has a great impact on the life safety of the wounded. (3) burn first aid should first remove the burn source, move the wounded to a place with good air circulation as soon as possible, and wrap the injured surface with clean clothes to prevent re-pollution; At the scene, except for chemical burns, which can be washed with a large amount of flowing water, the wound is generally not treated, and the blisters are not broken as much as possible to protect the epidermis.
2. Treatment of closed trauma ① Slight closed trauma, such as local contusion and subcutaneous hemorrhage, can be cold compressed at the injured part to prevent tissue swelling and reduce subcutaneous hemorrhage. (2) In case of accidents such as falling from a height or being injured, the patient shall not be moved at will.
(3) If internal injuries are suspected, the wounded should be treated as soon as possible; When transporting the wounded, take a lying position, handle carefully, keep the respiratory tract unobstructed, and prevent shock. (4) In case of respiratory and cardiac arrest during transportation, first aid measures of artificial respiration should be taken immediately.
Related news link: ■ A falling accident occurred in the wire and cable factory in the eastern suburb of Chifeng City, Inner Mongolia, causing 1 person to die. Workers in this cable factory are installing boilers. The asbestos tile on the roof of the boiler needs to be removed to install the boiler. The worker went to work on the roof without any protective equipment. As a result, the asbestos tile was accidentally crushed, causing the asbestos tile to fall off the roof and die.
■ A construction accident occurred when a construction company in Shanghai dismantled the safety net, and three people died. Three workers of the construction company did not check carefully before dismantling the safety net, and found that the fixed point on the east side of the safety net had been destroyed.
When three people step into the flat net,
4. What problems will occur in the process of building construction?
I. Causes and preventive measures of floor cracks in buildings First of all, there are several main reasons for floor cracks in precast hollow slabs: 1. Because the workers failed to remove the residue of broken bricks, wood blocks, mortar and so on in time, and the board was dry when the board was filled, it was difficult to make the fine stone expansive concrete and the board firmly stick together, resulting in cracks between the concrete and the board; 2. Cracking is due to the pre-embedded electrical conduits in the slab joints, and the designer has set some electrical conduits in the slab joints, so that the concrete in the slab joints is not filled or poured, and the ground plastering here is cracked; 3. During construction, the floor slab was not leveled with cement mortar or installed with mortar to stabilize the floor slab.
When the floor is stressed, it produces displacement, which makes the adjacent floor move up and down and produces cracks; 4. Because the concrete at the slab joint fails to reach the design strength, it will bear the construction load prematurely and produce cracks; 5. During the hardening process of slab joint concrete, with the increase of strength, shrinkage deformation and cracks also occur, leading to floor cracking. In view of the above reasons, the main preventive measures are as follows: (1) When designing, the slab joint should be widened appropriately; generally, 100mm should be equipped with steel bars, formwork should be hung at the bottom of slab joint, and c20 fine stone expansive concrete should be poured to make slab joint and floor slab form a whole.
(2) When designing, try not to set electric conduit at the joint of the board, so as to avoid the joint of the board being not dense. (3) Try to use concrete expansion agent to avoid throwing ordinary concrete to resist concrete shrinkage and deformation.
(4) Carefully clean up the residual sundries in the slab joints, rinse the ground with clear water, mechanically vibrate the concrete, and keep in good health in time. (5) Before installing the floor slab, level it with cement mortar and spread it on the floor slab, so as to avoid loosening of the floor slab and shearing force between adjacent slab joints due to mutual dislocation.
(6) After slab joint pouring, the construction load should not be increased prematurely to prevent the concrete in slab joint from vibrating and reduce the strength. Secondly, the common causes of cracks on the edge of precast slab bracket are: 1. The precast reinforced concrete floor is simply supported, and under the action of service load, the end of the floor will have angular displacement, which is easy to cause cracks at the joints of the floor. 2. Shrinkage deformation of precast reinforced concrete floor will also cause cracks in the floor; 3. In design and construction, sometimes one end of the floor slab is supported on the reinforced concrete frame beam, and the other end is supported on the brick wall.
Because of the different settlement of the two structures, the plate end is deformed and cracks appear in the floor supported on the beam; 4. Both ends of the precast floor slab are supported on two brick walls, and the slab ends will be deformed due to the different settlement of the two brick walls; 5. Due to the different specifications of precast floor slab, when the temperature changes, different deformation will also cause cracks in the floor slab; 6, when installing the floor, don't sit on the pulp, make the plate bearing loose, also can produce cracks. The main preventive measures are as follows: (1) In the design, try to avoid supporting both ends of the floor on the reinforced concrete frame beam and the load-bearing wall respectively, so as to reduce the settlement difference of the bearings at both ends of the floor and avoid cracks in the floor at the bearings.
(2) Reinforced concrete steel wire mesh can be set as far as possible in the floor leveling layer to enhance the integrity of the floor and the ability to resist negative bending moment. When it is not possible to set all the steel mesh, 600-wide reinforced concrete steel mesh can also be set on the floor supported by the plate. (3) During construction, the floor must be installed with cement mortar and the ends should be leveled.
(4) If necessary, frame joints can be reserved at the bottom of the plate and sealed with building sealant. Second, several main measures to build a good rubble foundation There are several main measures to build a good rubble foundation: (1) Master the consistency of masonry mortar.
Improper water-cement ratio of mortar will cause poor compactness and fullness of mortar. When laying rubble, due to the small water absorption and large mortar joint, a water film will be formed between the stone and mortar, which will increase the sliding of rubble and reduce the strength of rubble foundation.
Therefore, the water-cement ratio of mortar should not be too large, and it should be adjusted according to the construction site and season. (2) Use the correct paving method.
When the amplification foot of rubble foundation is stepped, the stones on the upper step should be at least 1/2 of the lower step, and the rubble on adjacent steps should be staggered and overlapped. When laying rubble foundation steps, larger or wider stones should be selected for the skin before the closed platform, so that rubble in the closed platform can at least hold down 1/2, so as to improve the uniformity of rubble foundation.
(3) Prevent rubble foundation from freezing in winter. In winter construction, after laying rubble every day, the surface of rubble foundation should be covered with thermal insulation materials or constructed with mortar mixed with additives.
When the lowest temperature during construction is below-15℃, the label of masonry mortar shall be increased by one level at room temperature. When the temperature is below -20℃, the construction shall not be continued, otherwise the water film between rubble and mortar will freeze, and there will be a gap between mortar and rubble after thawing, which cannot form a whole.
Three. Common problems and measures in pile foundation construction (1) Long spiral bored pile: Long spiral bored pile is widely used in geological conditions without water and sand. Its advantages are high construction speed and easy quality assurance. However, the following problems are easy to occur in construction: when the drilling rig reaches the elevation of the bottom of the hole, it should stop drilling and make static dialing. For example, when drilling and lifting drill pipe, a large amount of virtual soil will be produced at the bottom of the hole, which will reduce the bearing capacity of the pile end. Before pouring concrete, 30-20cm gravel should be poured, tamped with a rammer, and then poured into a reinforcing cage to pour concrete.
The slump of pouring concrete should be controlled at 10cm. If the slump is too small, it is easy to break the pile, so the whole process should be vibrated when pouring concrete. (2) Vibrating bored pile (vibrating bored pile): Vibrating bored pile can be constructed in groundwater, muddy soil and silty sand layer with a thickness of less than 3m, and the construction cost is lower than other underwater piles, but the pile cannot penetrate silty sand layer and medium sand layer with a thickness of more than 3m during construction.
Subject to certain restrictions. Pile construction can not control the elevation alone.
Must be subject to dual control. It is normal for piles in the same community to have different lengths.
When the pile does not reach the design elevation, it is forbidden to vibrate for a long time, otherwise the diameter will be reduced or adjacent piles will be broken. In order to improve the bearing capacity of the pile during construction, it should be piled again, and the soil on the vibrating tube must be cleaned before construction.
It is forbidden to insert into the soil, because it is easy to bring mud into the pile and cause pile breakage. (3) Pressure grouting pile: Pressure grouting pile is a kind of sand-free concrete filling pile. Cement slurry seeps into the soil around the pile, which improves the bearing capacity of the pile. The bearing capacity in sandy soil is 1. 1~2 times that of ordinary piles, and it is suitable for most geological conditions.
5. Excuse me, a question about building foundation.
These are the most basic common sense in civil engineering.
The foundation is to bear the self-weight of the building and stabilize the building against comprehensive external forces.
Bearing and stabilizing structure
There are many kinds of foundations, such as raft foundation, box foundation, independent foundation under column, strip foundation and cap foundation.
Brick foundation, as its name implies, is the foundation made of brick, which is based on the basic performance required by the building.
A building can be composed of multiple foundations at the same time, but the foundation should meet the bearing capacity requirements of the foundation as well as the superstructure.
Basement engineering generally adopts raft foundation or box foundation for design and construction.
When the bearing capacity of natural foundation soil is insufficient, the foundation needs to be treated, or
Piling is required, and then the foundation is positioned on the pile cap.