1、Chapter VIIIQuality and safety of engineering construction1. Construction quality of earth foundation1.1 General rulesGBJ 202-831.0.3 When engineering construction work for earth base and foundation is adjacent to existing construction or structural items, the following shall be observed:IBefore sta
2、rting construction work, details of the original structure of existing buildings or structural items shall be informed of.IIConstruction work for earth base and foundation, if affects use and safety of adjacent buildings or structural items, effective measures shall be taken together with institutio
3、n concerned.1.0.4 Category, size standard number and concentration of materials and manufactured products shall meet designing requirements.1.0.7 During construction of earth base and foundation, hidden items shall be inspected and accepted in intermittence, only after qualified can the next procedu
4、re be continued. After finished, it shall be accepted by inspection.1.08 Earth base and foundation construction in winter shall meet the following rules:IIce and snow at site ways and construction place shall be cleaned away.IIFrozen soil that affects construction work shall be dug out and removed;
5、freezing prevention measures shall be taken.IIIFrozen materials are prohibited to use.1.2 Soil with special propertiesGBJ 25-905.1.1 Construction of buildings and their attached projects shall be in a reasonable sequence according to specific characteristics and designing requirements of wet-pitfall
6、 loess to prevent construction used water and rainwater flow into the earth foundation, which leads to wet-pitfall.5.4.5 When crack of building due to wet-pitfall of foundation is found, construction work shall stop temporarily, shut off water source concerned, find out cause and range of water subm
7、erging and observe sink and cracking of the construction, draw and record; continue construction work after the problem has been treated.GBJ 112-8724.1.3 Water for construction shall be managed perfectly to prevent leakage of piping network. Distance between outside wall of building and temporary wa
8、ter pool, material washing site, ash cleaning pool, flood-preventing ditches, agitating station shall not less than 10m. Temporary living facilities shall be more than 15m away from buildings. Water displacing facilities shall be provided perfectly to prevent construction use water from flowing into
9、 foundation pit (ditch).4.2.2 Sunlight-exposure and water submerge are prohibited during construction. In rainy season, prevention for water flooding should be performed.1.3 Piling foundationJGJ 94-946.1.3 Pile preparing machines must be qualified by appraisal, otherwise is not allowed to use.6.1.6
10、Control point of foundation pile axis and benchmark points shall be setup at place where construction work does not affects. These points shall be repeatedly checked and then protected carefully and rechecked from time to time during construction work.6.2.3 When hole-preparing equipment is located t
11、o position, it must be level, stable, and firm to guarantee that no inclination, motion shall occur. To control hole depth preciously, scale for controlling hole depth shall be equipped on the piling shelf or pile pipe so as to observe and record.6.2.13 Manual digging hole piling work shall take the
12、 following safety measures:6.2.13.1 Emergent soft ladder shall be equipped in the hole for workers to go down and come up. Electric lifter and lifting cages must be safe and reliable and with automatic locking device. Workers are not allowed to go down or come up by linen or nylon ropes, neither by
13、climbing the well wall. Electric lifter shall be inspected for its lifting capability before it is used.6.2.13.2 Hazard gases in the well, if any, must be examined before work everyday and must provide sufficient safety protection measure. When digging depth is beyond 10m, Special device for ventila
14、tion in well shall be provided.6.2.13.3 Protection handrails shall be setup around the pit opening, of which the height is usually 0.8m.6.2.13.4 Stone and soil dug out shall be removed far away from the pit opening. It is not allowed to pile stone and soil within 1 meter around the pit. Vehicle tran
15、sportation must not affect safety of well wall.6.2.13.5 Installation and dismantling any electric power, wires at construction site must be performed by licensed electricians. Electric devices must be earth grounded or connected to zero voltage point and equipped with breakers for electric leakage.
16、Protection. Electric devices must use breakers or knife-switches individually and one switch for several devices is seriously prohibited. Cables over the pit shall be more than 2.m overhead and lying on ground or burying underground are prohibited either. Protection measures as abrasive-proof, humid
17、-proof, breaking-proof shall be taken for electric wire. Safety mining lamps or safety lamps with voltage bellow 12V shall be used for illumination.6.3.18 Reinforcing steel bar cage, when finished lifting, shall be inspected for acceptance as 3 hidden items, after qualified, concrete sludge shall be
18、 poured immediately.7.2.1 Only when the pre-cast piles reach 70% of designed strength can they be lifted, and after reach 100% for transportation.7.4.1 Overhead and underground obstacles must be removed before sinking the piles, when the site must be flat and tidy and water displacement fluently gro
19、und surface load bearing capability satisfactory,9.1.4 For engineering construction of class 1 construction piling foundation or piling foundation construction work whose geological condition being complicated or reliability rather low, quality of pile preparation shall be tested and measured. Data
20、for measurement shall be determined in designing according to actual circumstance.1.4 Supporting-protecting foundation pitJGJ 120-993.7.1 Plan for digging foundation pit shall performed according to design of support-protecting structure and requirement of water displacement.3.7.2 Water ditches shal
21、l be equipped around the pit on ground and leakage and penetration to pit shall be avoided; When the pit is dug with slope lowering and displacing water devices shall be arranged at slope top, slope surface and slope foot.3.7.3 Over load around the foundation pit is seriously prohibited.3.7.4 Founda
22、tion pit with soft soil must be dug for layers evenly.3.7.5 During digging foundation pit, measure shall be taken to prevent the supporting-protecting structure, engineering piles from being knocked or shocked, neither to disturb the original status of soil in the pit bottom.3.7.6 When abnormal circ
23、umstance occurs, stop digging, find out the cause and take measures, immediately, only after these measures taken can continue digging.4.7.4 Construction for supporting system shall meet the following requirements:1Sequence for installation and removing of supporting structure should be correspondin
24、g to the operation condition when designing the foundation pit supporting structure. The principle that first supporting and then digging must be observed.2At locations where the vertical column goes through the bottom plate of main structure and where the supporting structure goes through the basem
25、ent external wall of the main structure shall be of a water-prevention structure.3Connection between top head of steel support and cap beam or waist beam shall meet the following rules:Steel plate with thickness no less than 10mm shall be setup at the top head of steel support as head-sealing plate,
26、 which shall be fully welded to the supporting rod with welding seam thickness and length that are capable for all supporting load or stress. If necessary reinforcing rib plate shall be added, of which the quantity and size shall meet the requirement of stability of local supporting top end and requ
27、irement of transferring supporting stress.4Pre-pressing for steel supporting member shall meet the following requirement:41) After supporting is installed, circumstance of connection between joint nodes shall be inspected in time, only it is confirmed meeting the requirement can pre-pressing operati
28、on starts. Adding pre-pressure shall be done upon both ends of the support symmetrically.2) Pre-pressing stress shall be acted in steps and repeatedly. When it reaches the designed value, joint nodes shall be checked again and reinforced if necessary. The pre-pressing mechanism shall be locked after
29、 pressure becomes stable.7.3.2 Section length of arch wall that is constructed along horizontal direction shall not be longer than 12m, it shall not be longer than 8m when goes through sift and weak soil layer or sand layer.1.5 Treatment of earth foundationJGJ 79-913.4.2 Bedding coarse shall be insp
30、ected for quality in layers. When each layer is rammed to dense, average pressing-dense coefficient shall be inspected, only when it is qualified can the next layer be laid on.3.4.4 Quality inspection for heavy-hammering, in addition to construction work record that shall be checked according to tes
31、t ramming, the total ramming down amount shall not be smaller than 90% of amount in testing ramming.4.4.1 For important engineering project for anti-slippery control, preserved holes shall be selected at places that can represent the condition in the pre-pressing area. Anti-shearing strength test wi
32、th cross plate and laboratory soil test shall be performed at different depth during different stages of loading.4.4.2 Relation curved lines such as deformation to time, pore water pressure to time shall be sorted out during pre-pressing period to plot and calculate the final solidifying deformation
33、 amount of foundation, solidity, and corresponding deformation amount to analyze treatment effect as base of determining unloading time.4.4.4 Earth foundation, after being pre-pressed, Shall be tested for shearing strength with cross plate and laboratory earthwork test to calibrate treatment effect.
34、5.4.1 Check various data and construction records made during forced ramming construction work, if the result does not satisfy requirement of design, ram again or other measures shall be taken.5.4.4 Quantity of samples for quality inspection shall be determined according to complexity of site and im
35、portance of the building in construction. For common buildings in simple site, no less than 3 points for each foundation of a building; for complicated site or important buildings inspection points shall be increased. Depth for inspection shall not be less than depth designed for treatment.6.4.1 Ins
36、pect vibration-shock in construction and various construction records, if any missing or unqualified pile or vibration-shock point occur, perform again or effective measures shall be adopted.6.4.5 For vibration-replacement engineering of large scale, important or those in complicated 5 site, inspect
37、ion for treatment effect of combined foundation.7.4.1 Samples shall be taken in time for inspection of quality of foundation treating effect of earth-squeezing or ash-earth-squeezing piles 7.4.2 Samples for the above-mentioned inspection shall not be less than 2% of the total pile holes. Remedy or a
38、dditional piles shall be provided at unqualified location.8.4.1 Construction and test results of pipe sink time of sandstone piles, amount of sand filled in each section, raising and pressing time and deviation of pile position. If any unqualified, remedy shall be done.8.4.3 For inspection of pressi
39、ng-to-dense result, it may be performed by picking up samples at random with samples no less than 2% of total hole quantity; if result shows that 10% piles do not reach designed requirement, add more piles or take other measures.9.4.2 Pile reinforcement earth samples shall be taken with a portable c
40、ontacting drill within 7 days after the agitated piles are finished preparing to observe the uniformity of agitation, also pile strength shall be checked and judged by number of hitting with the portable contacting drill. Quantity of piles for checking shall not be less than 2% of piles piled.9.4.3
41、Sampling, single pile load bearing test or digging out test shall yet be done if under the following situation:IPile core sample shall be taken and make into test blocks from piles that are suspected to have strength lower than standard and determine the actual strength.IIPiles in complicated site o
42、r construction work for piling has problem, single pile load bearing test shall be performed to inspect its load bearing capability.IIIFor strict engineering project that has strict requirement on overlapping joint of adjacent piles, when piles have been cured till a certain period, several piles sh
43、all be dug out to check outside quality of pile top visually.10.4.3 Quantity of points for inspection of high pressure spraying mortar shall be 25% of holes that have been sprayed with mortar. For projects whose holes are fewer than 20, at least 2% points shall be inspected. Re-spraying should be do
44、ne for those unqualified.2. Construction quality of concrete structure2.1 General rulesGB 50204-921.0.4 Construction of concrete structure project shall be performed according to design drawings.Partial construction work of concrete structure shall be performed after the former part has been inspect
45、ed as qualified.3.1.2 Steel bar shall have quality certificate or test report. Markings shall be tied on surface 6or at each bundle of steel bars. Acceptance inspection shall be carried out per hot number (batch number) and diameter of bars. Inspection includes marking, visual check, and dynamic pro
46、perty test, only qualified ones can be used.During processing, if steel bar broken due to brittleness, bad welding or unqualified dynamic property is found, chemical composition test or other specific test shall be performed.4.1.3 Cement must have quality certificate or test report for acceptance an
47、d category, mark number, packed or bulk delivery number, leaving factory date all shall be checked before acceptance.When quality of cement is suspected, or cement left factory more than three months before ( none month for rapid-curing portland cement silicate) , a repeat test shall be performed to
48、 determine whether it can be used or not.GB 50164-923.1.3 Safety and strength shall be tested for cement to be used. If required, other properties shall yet be checked.GB 50204-924.1.6 aggregated materials shall be piled per category and size respectively and not to mix them. Calcinated dolomite or
49、limestone is seriously prohibited to mix in the aggregate.JGJ 52-923.0.7 For sand used for important concrete in engineering project, alkali activity test shall be done for concentrated material with chemical method or mortar length method. If, through the above-mentioned test, it is determined to be potentially harmful, the following measure shall be taken:3.0.7.1 Use cement that contains water content below 0.6%, or use blending material that can inhibit reaction between alkali and concentrated material.3.0.7.2 When additives that contain potassium and soda ions, special
