土建项目冬季施工-中英对照
本项目施工周期跨越北方初春和冬季两个严寒季节,周密的冬季施工措施是整个项目工程质量的有力保障.
第一节 冬季施工部署
1､冬施责任分工,见下图.
冬施责任分工
2､提前编制钢结构､土建､和装修施工冬施方案,并组织施工管理人员和工人进行培训.
3､编制防火预案,检查各楼层消防水管和灭火器,对管理人员和工人进行防火知识培训.
第二节 技术和材料准备
1､在冬期施工前完成钢结构冬季焊接工艺评定.
2､要求混凝土供应公司､试验室要做好冬期混凝土､砂浆所掺外加剂的复试试配工作,提前做好负温养护混凝土的配合比试验.
3､冬施材料､机具准备
冬施前准备:加热器(100台)､电子温度计(1个)､电子测温仪(4个)､阻燃草帘被､聚苯板和塑料布(各6000m2),见下图.
电子测温计 阻燃草帘被
试模 混凝土测温计
冬施材料准备
4､现场外露水管､消防管保温,见下图.
现场外露临水管､消防管保温
5､大型机械要做好冬期施工所需油料的储备和工程机械润滑油的更换､补充以及其它检修保养工作,以便在冬施期间运转正常.
第三节 土建防冻要点
1､重点部位保温措施
(1)冲压平台基础和水泵房地下室等混凝土保温
大体积混凝土采用综合蓄热养护法.
混凝土浇筑前,用铁丝在大钢模背面固定5cm聚苯板+2层塑料布.
混凝土达到临界强度(>4MPa)后,拆除钢模板并利用穿墙螺杆和铁丝在混凝土表面固定一层塑料布和两层阻燃草帘被.
地板混凝土保温
(2)室内土方回填
回填前,彻底清理基底冰水和杂物.
回填土料不含冻土块.
土方回填时地下室结构已经施工完毕,在于大气连通的大门洞设置防风门帘,有利于提高室内温度,当室内气温小于0oC时,暂停回填作业采用分层回填,每层厚度不超过20cm,并采用人工+机械夯实.
(3)室外土方开挖和回填
对开挖管沟的侧边和基槽覆盖2层草帘被保温.
采用分层夯实回填法,每层厚度不大于20cm.
暂停作业时,对表面土覆盖2层草帘被+塑料布进行保温防雨雪.
2､混凝土测温
(1)测温起始时间:室外日平均温度5d稳定低于5℃即应开始测温.测温工作内容:包括大气､原材､入模和养护温度.
（2） 测温点布置:测温点沿梁每3m一个且每跨至少2个,楼板每15m2一个,柱头､柱脚各一个,剪力墙延轴线布置3点(每点在墙顶和墙脚分别距上下边缘30-50cm布置一个).
（3） 测温频率:大气温度在7:30,14:00､21:00各测一次,且每班三次.掺防冻剂的混凝土浇筑后临界强度达到之前每2h测温一次,临界强度达到之后每6h测温一次.
（4） 测温数据处理:每次温度测定后输入计算机,自动生成温度曲线和混凝土强度计算值,详见下图.
测温及数据处理
3､钢筋防冻注意点
(1)在负温条件下使用的钢筋,施工时应加强检验.遇雪天时,绑扎好的钢筋要用塑料布遮盖严密,防钢筋表面结冰霜.浇筑混凝土前及时将冰､雪等清理干净.
(2)在负温条件下局部钢筋的焊接,应有遮挡棚,温度不得低于-20℃,焊后的接头严禁立刻碰到冰雪.
4､混凝土防冻注意点
(1)在浇筑前,要清除模板和钢筋上的冰雪和污垢.
(2)在施工缝处接着浇筑混凝土时,应先除掉水泥薄膜和松动石子,湿润冲洗干净,待已浇筑的混凝土强度高于1.2Mpa时允许继续浇筑.
(3)混凝土浇筑后应在裸露混凝土表面采用塑料布､草帘等材料覆盖并进行保温;对边､棱角部位的保温厚度应增大到面部位的2~3倍,并压紧填实､周圈封好;保温层要干燥;混凝土养护期间应防风防失水.在白天正温时进行测量放线,放线必须掀开保温材料时,要尽量减少掀开面积,放完线后应立即覆盖.
(4)保证混凝土出机温度不低于15℃,入模温度不低于5℃.
(5)冬施混凝土要比常温下增设两组试块同条件试块,并填写混凝土搅拌记录.其中一组试块用于抗冻临界强度测试,约3~7天,应与测温结合起来.在结构混凝土温度降到抗冻剂规定温度前,计算混凝土强度是否超过抗冻临界强度4N/mm2(气温不低于-15℃时),如达不到则应增加保温､加热养护等措施,使受冻面强度超过临界强度.另一组试块转入常温养护28d.
Chapter Two Winter constructions
The construction period of the project is across two cold seasons of early spring and winter in northern area. Therefore, a well-planed winter construction measure shall be the effective protection for the quality of the entire projects.
Section I Construction assignment in winter
1. Winter construction division of responsibilities is as follows.
项目经理（总负责）
总工（冬施工方案，措施）
现场经理（现场实施，监控）
物资经理（材料准备，供应）
技术部（方案措施编制）
工程部（现场监督实施）
物资部（物资购买，供应） Project Manager (overall responsibility)
Chief Engineer (winter construction plan, measures)
Site Managers (field implementation, monitoring)
Materials Manager (material preparation, supply)
Technology (program measures compilation)
Engineering Department (site monitoring implementation)
Materials Department (material purchase, supply)
Winter construction responsibility assignment
2. Prepared the winter construction plan of steel structure, civil and decoration in advance, and organize the training program for the administrative stuff and workers of construction.
3. Prepared the fire plans, check the fire hoses and fire extinguishers on each floor, and organize the training program of fire safety for managers and workers of construction.
Section II Technology and materials preparation
1. Finish the winter welding technology evaluation of steel structure before the winter construction.
2. Check the reexamining and trial operation of winter concrete and mortar admixtures of concrete supply company and laboratory; finish the concrete mix test of concrete curing in negative temperature in advance;
3. Winter construction materials and equipment preparation
Preparation for winter construction: heater (100 units), electronic thermometer (1), electronic thermo-detector (4), anti-flaming straw cover, polystyrene board and plastic cloth (6000m2 respectively), see the following picture;
Electronic thermo-detector Anti-flaming straw cover
试模 Die trial Concrete thermo-detector
Winter construction material preparation
4. On-site exposed pipeline and fire pipe insulation; see the following picture.
On-site exposed pipeline and fire pipe insulation
5. Prepare the replacement, supplement and other repair and maintenance work of fuel oil reserve and engineering machinery lubricating oil of the large machinery in winter, so as to ensure the normal operation of the facilities during the winter construction.
Section III Main points of antifreeze measures of civil construction
1. Insulation measures of key positions
(1) Concrete insulation of punching platform foundation and the basement pump room;
● Mass concrete applies the comprehensive thermal storage method.
● Before concrete pouring, fix 5cm layer of polystyrene board and 2 plastic cover with steel wire in the back of a large steel mould.
● After the concrete reaches a critical strength (> 4MPa), remove the steel mould and fix use through the wall of steel and wire screw in the concrete surface a layer plastic sheeting and two layers of flame-retardant straw cover.
Floor concrete keeping warm
(2)Indoor earthwork backfill
● Before backfilling, completely clear up frozen water and incidental of foundation base.
● The backfilling soil does not have the frozen soil;
● The construction of basement structure has already completed at the time of earthwork backfill. The windproof curtain shall be located in the main opening where the atmosphere feeds through, so as to improve indoor temperature; when the indoor temperature is lower than 0oC, suspend the backfill work.
● Adopt the method of backfilling in layer, the thickness of each layer shall not exceed 20cm, and applies the manual and machinery tamping.
(3) Excavating and backfilling in outdoor earthwork
● Apply the insulation measure to the excavation trench and cover 2 layers of grasses curtain on the base trough.
● Adopt the method of backfilling in layer, the thickness of each layer shall not greater than 20cm.
When the construction work is suspended, cover the surface soil cover grass curtain with 2 layers + plastic cover for keeping warm.
2. Measuring the concrete temperature
(1)Initial time of temperature measuring: start to measure the temperature while the average outdoor temperature of the 5d is stabilized lower than 5 degrees Centigrade. Temperature measuring includes: atmosphere, raw material, in-mould and curing temperature.
(2) Arrangement of temperature measuring area: temperature measuring area shall be located along roof beams every 3m and at least 2 temperature measuring area shall be arranged; each floor shall have one temperature measuring area every 15m2, and each column cap and post foot shall have one temperature measuring area respectively; the shear wall shall arrange 3 temperature measuring area alone the axis (each temperature measuring area shall be located on the top of the wall or the foot of the wall about 30-50cm away from upper and lower edge respectively).
(3) Frequency of temperature measuring: measure the atmosphere temperature at 7:30, 14:00 and 21:00 respectively, and three times of each shift. Measure the concrete temperature 2h before the concrete reaches the critical strength, which mixed with antifreeze after pouring; measure the concrete temperature 6h after reaches the critical strength.
(4) Data processing of temperature measuring: Input the measured data into computer, which shall be automatically illustrated as temperature curve and calculating value of concrete strength; details as shown in the following picture.
Data processing and temperature measuring
混凝土测温 Concrete temperature measuring
测温输入电脑 Input the temperature data into the computer
生产测温曲线 Production temperature measuring curve
3. Notice of reinforcing bar anti-freezing
(1)The reinforcing bar used under the negative temperature, it shall strengthen the inspection procedure in construction. In snowing weather, the fixed reinforcing bar shall be tightly covered with the plastic cloth for preventing ice cover and frosting on the reinforcing bar surface. Clean the ice and in time before the concrete pouring.
(2)The welding of some reinforcing bar under negative temperature shall equip with shelter canopy, and the temperature shall not be lower than -20 degrees Centigrade; the joints after welding shall not contact the ice and snow at once.
4. Notice of concrete anti-freezing
(1) Before concrete pouring, remove the snow and dirt on the template and reinforcing bar.
(2) When continue the concrete pouring in the construction joint area, remove the cement cover and loosed stone at first, rinse moistly well, when the intensity of pouring concrete is higher than 1.2Mpa, then continue the pouring process.
(3) The concrete surface after pouring shall be covered with plastic cloth, grass curtain for keeping warm; the thickness of concrete insulation in opposite side and raised angle position shall be 2 times of the surface area, tightly compressed and well covered; The insulation layer will be dry; The concrete shall be protected from wind and water losses in concrete curing. Apply the survey layout when warm in the daytime; when the survey layout need to raise the insulation layer, it shall be covered with immediately after the survey layout finished, and reduce the opening area as far as possible.
(4) Ensure the temperature of the concrete from machine is not lower than 15 degrees Centigrade; the in-mould temperature of concrete shall not be lower than 5 degrees Centigrade.
(5) The concrete construction in winter shall arrange additional two groups of testing piece than the construction under the normal atmospheric temperature; and fill in the concrete mixing record. One group of testing piece shall be used for critical strength test of anti-freezing, which shall take 3-7 days together with temperature measuring. Before the temperature of structure concrete is lower to defined temperature of antifreeze agent, calculate whether the concrete strength excess the critical strength of freeze 4N/mm2 (the temperature shall not be lower than - 15 degrees Centigrade); otherwise, it shall take the insulation and curing measure to keep worm; and ensure the intensity of cold surface exceed the critical strength. Another group of testing piece shall enter into the normal atmospheric temperature and maintains for 28d.
2013.1.30