(A) concrete supply: 1, commodity concrete: to adopt the ISO9002 quality certification of the manufacturer, according to the actual situation of the project on its production technology monitoring requirements are as follows: (1) material requirements: A, bulk cement: a cement Use 325 or more ordinary Portland cement or Portland cement. b. When cement enters the factory, there should be a factory certificate or test report, and check its varieties, marking the date of manufacture. If found to be damp or expired before use, the sample should be resampled. c. Quality indicators in the cement quality indicators should be consistent with the provisions of the standard. Quality indicators include magnesium oxide content, sulfur trioxide content, loss on ignition, fineness, setting time, stability, compressive strength and flexural strength. d. The maximum amount of concrete cement should not be greater than 550kg / m3. B, sand: a. Sand to be the preferred Shenzhen dock high-quality river sand. b. Concrete projects should be selected coarse sand. For pumping concrete, sand should be used in sand, sand rate should be controlled at 40 ~ 50%. c. Sand content (by weight), not more than 3% when the concrete strength level is higher than or equal to C30, not more than 5% below C30, for impermeability, frost resistance or other special requirements Of concrete sand, the clay content should not exceed 3% of C10 or C10 below the concrete sand, the mud content may be relaxed as appropriate. C, gravel (gravel or pebbles) a. Granite should be used as a good stone. b. The maximum size of the stones shall not be greater than 1/4 of the cross-sectional dimension of the structure and not more than 3/4 of the minimum clearance between the bars. Concrete aggregate aggregate maximum size should not exceed the thickness of the plate 1/2. And shall not exceed 60mm. For pumping concrete, the ratio of the maximum particle size of gravel to the inner diameter of the pipe should be less than or equal to 1: 3 and the pebble should be less than or equal to 1: 2.5. c. The amount of clay in gravel (by weight) is not more than 1% for concrete equal to or higher than that of C30; not more than 2% for materials less than C30; for mixtures with resistance to freezing, impermeability or other special requirements Condensation, gravel content of not more than 1%; for C10 or C10 below the concrete, gravel content of mud can be relaxed as appropriate. d. The content of the medium needles and flaky particles in gravel (by weight), not more than 15% when the concrete strength level is higher or lower than C30; not more than 25% lower than C30; Can be relaxed to 40%. D, water: drinking water in line with national standards can be mixed all kinds of concrete, do not need to be tested. (2) Operating Conditions: a. When the task list is issued, the name, location, location and quantity of the project must be included. The technical requirements (strength grade, retardation and special requirements), on-site construction methods, production efficiency Construction period), the requirements of handing over and connecting, and the contents of coordination between supply and demand sides, together with the construction mix notice issued. b. The equipment is running normally and the number of concrete transport vehicles meets the requirements. c. adequate supply of materials, in particular the designated cement varieties have sufficient reserves or follow-up supply guarantee. d. All materials should be tested and qualified to meet the requirements. e. mixing station, pouring pounding site and transport vehicles have a reliable means of communication between. (3) The quality inspection requirements of commercial concrete: a. Pumping concrete, work for each class more than 100m3 of the project, should be sent to the quality inspector. b. Concrete mixer truck out of the station, each car must be checked by the quality inspector and transmissibility of visa compliance. Slump Sampling once per car; concrete truckload check each mix of not less than once a day. c. When sampling on site, the concrete should be represented by 1/4 to 3/4 after discharging the mixer. Concrete sampling, specimen production, conservation, both parties should be both signed by the supply and demand approval. d. Mixing truck shall not appear before discharge and initial setting phenomenon. 2, self-mixing concrete production: Self-mixing concrete used to prevent the temporary provision of commercial concrete emergency measures and sporadic concrete on-site mixing, raw materials and mix should be consistent with the commercial concrete. (1) According to the ratio of each plate (slot) the amount of various materials to be said. (2) loading order: general first installed gravel, then install the cement, and finally loaded sand, if you need to add admixture, it should be added together with the cement. (3) The minimum time for concrete mixing is determined according to the requirements of the construction specifications. When admixture is added, the mixing time should be extended appropriately. Fly ash concrete mixing time than the reference mixed soil to extend 10 to 30s. 3, concrete transport: (1) concrete transport vehicles in the field trolley, bucket, chute (basement -), pumping and so on. (2) After the concrete is discharged from the mixer, it should be promptly transported to the place of pouring for the duration, which can not exceed the initial setting time. In the transport process, to prevent concrete segregation, loss of cement slurry, slump changes and the phenomenon of initial setting. If the concrete is transported to the place of pouring, there must be the second mixing before watering on the scene of segregation. (3) Concrete transport roads should be smooth and smooth, if uneven, should be paved bridge 枋. In the construction of the floor, it should be laid a special bridge is prohibited bar stamped personnel and staff. (B) pumping concrete: 1, pumping process: (1) before pumping concrete, the first hopper water pump out from the pipeline to achieve the purpose of wetting and cleaning pipes, and then added to the hopper with the same proportion of concrete Of the cement mortar (or 1: 2 cement mortar), the pump can start after the pumping of concrete. (2) When starting to pump, the pumping speed should be slowed down. The change of hydraulic pressure should be within the allowable range. When the pumping is smooth, it should be pumped with normal speed. (3) During pumping, the amount of concrete in the hopper should be maintained at a minimum of 10 mm above the cylinder bore to 150 mm below the hopper mouth. Avoid inefficient inhalation, easy inhalation of air caused by the tube, too much when the counter will overflow and increase the shaft load. (4) Concrete pumping should be continuous operation, when the concrete supply is not timely, to reduce the pumping speed, pumping temporarily suspended, stirring should not stop. When the leaves are stuck, the need to reverse queuing, and then forward, reverse a certain period of time, to be smooth before continuing to pump. (5) if the pumping midway stop time more than 20min, the pipeline is longer, the pump should be open every 5min, pumping a small amount of concrete, the pipeline is shorter, you can use positive and negative every 5min trip 2-3, Make the concrete creep in the pipe to prevent segregation of bleeding water, long time to stop pump (more than 45min), high temperature, concrete slump hours may cause plug pipe, concrete should be removed from the pump and pipe. (6) pumping away after the recent pouring gradually demolition. (7) pumping in the hot season, should be covered with warm grass bag pipe cooling to reduce the mold temperature. (8) The sum of the horizontal conversion distances of the pumping pipes shall be less than the maximum pumping distance of the equipment. (2) When the pumping is finished: (1) At the end of pumping, the amount of concrete stored in the concrete pipe and hopper should be estimated and the amount of concrete (Φ150mm diameter pipes per 100 m) Mixing the amount of concrete. (2) When the pumping is completed, the air compressor is used to clean the ball when cleaning the pipeline. Put a good special wash water, then start air compressor, progressive pressure. During cleaning, the pipe should be tapped at any time to see if the concrete is close to emptying. When there is about 10m of concrete in the delivery pipe, the compressor should be slowly depressurized to prevent large explosion and injury. (3) After the pump is finished, the concrete pump, distributor and pipe should be cleaned immediately. After the pipe is disassembled, the pipes should be stacked according to different specifications. (C) the pouring of concrete: 1, concrete pouring before the preparation: (1) the organization of construction teams to pay technical note, the team must be familiar with the drawings, a clear construction site of various technical requirements (concrete strength grade, impermeability level, Time, etc.). (2) Organizing the team to hand over the rebar and template, if there is no concrete construction condition, the concrete construction can not be carried out. (3) Organization of construction equipment, tools and other supplies, to ensure good. (4) before pouring wetting template should be wet, wall, column template cleaning port should be cleared of debris and water and then closed. 2, the general requirements of concrete pouring: (1) Concrete falling from the mouth of the bucket free fall height of not more than 2m, such as more than 2m must take measures. Straps, tubes, chutes, or door shutters should be used on the sides of the formwork (raw mouth). (2) Pouring concrete should be segmented layering, pouring height of each layer should be based on structural features, steel density decision. General layered height of the role of plug-in vibrator part of the length of 1.25 times the maximum not exceeding 500mm. The thickness of the slab vibrator is 200 mm. (3) Start the vibrating rod, vibrate the hand grip flexible shaft hose at the top of the vibrating rod and quickly insert the interior of the concrete. When vibrating, the vibrating rod slightly tows up and down, vibrating for 20-30 seconds, Re-emergence of bubbles, no significant sinking, the surface of the slurry and surface formation level prevail. The use of plug-in vibrators should be inserted quickly inserted slow, plug points should be evenly arranged, point by point movement, in order, shall not be omitted, so that even solid. The moving distance is not more than 1.5 times the radius of vibration rod (usually 300 ~ 400mm), the distance from the template should not be less than 200mm. Vibrate the upper layer should be inserted into the lower concrete surface 50 ~ 100mm, in order to eliminate the seam between the two layers. The spacing of the plate vibrators should be such that the plate of the vibrator covers the edges of the tapped part. (4) pouring concrete should be carried out continuously. If it must be intermittent, its intermittent time should be shortened, and should be the first layer of concrete before the initial setting, the second floor of concrete pouring completed. Intermittent maximum time should be determined according to all types of concrete and concrete initial setting conditions, generally more than 2 hours should be handled by construction joints. (5) Concrete pouring should be sent to observe the regular template steel reinforcement, reserved holes, embedded parts, such as whether there is displacement deformation or plug tendons, and found that the problem should be immediately irrigated and concrete pouring has been completed before the initial setting . (6) pouring finished, check whether the reinforced concrete surface contamination, and timely scrub clean. 3, the wall concrete pouring: (1) before the wall pouring, or the new concrete and the lower burned concrete joints should be evenly poured on the bottom 50mm thick concrete mix with the same proportion of cement mortar. Mortar application shovel into the mold, do not use the hopper directly into the mold. (2) Wall concrete should be layered and vibrated, each pouring thickness control in about 500mm. Concrete cutting point should be scattered layout, recycling, continuous. (3) pouring wall hole, make the hole on both sides of the concrete height roughly the same. Vibration concrete to be even and dense, especially the wall thickness is small, the door and window structure reinforced with interlocking bars more dense parts should be Φ25 vibration rod, the other wall parts Φ50 vibration rod, taking into account the wall under the wall window After the concrete sealing mold can not be directly vibrated, you can leave the mouth of the window in advance to stay alive until the concrete pouring to the location and vibrate and then seal the mold and reinforcement. When vibrating, the vibrating rod should be 300mm above the edge of the hole and vibrate simultaneously from both sides to prevent deformation of the hole. Large holes in the lower part of the template should be opened and added vibration. (4)
Elevator Cable
Elevator ropes are highly engineered and made of steel with other composites. Also they are not single wires but several strands of various sizes wrapped together. A typical cable or rope can have over 150 strands of wire precisely designed to be strong, flexible, and give long service. Multiple wire strands are used to increase the life of the cable and give flexibility. When you run a cable over a pulley wheel or sheave, the part of the wire on the sheave makes a shorter trip than the outside of the wire. This stretching over time would create weakness for a single strand. So elevator ropes are flexible strong and give long life if maintained properly.
The types of rope in an elevator can vary depending on the job that they need to do. Here are some of the more common ropes you can find lurking in your hoistway:
1. Hoisting Ropes – These are the ropes you see in all the movies. Several are used to suspend the elevator cab and make the car go up and down. These are also the cables used for the counterweights as the counterweights and elevator car are in the same system. The counterweights do just what they are called; they counter the weight of the elevator car when loaded so it takes less effort to move the car up and down. High-strength ropes are used in high rises due to the required speeds that you see today. For instance the fastest moving elevator car in the world, hits a speed that you would find on freeways; an astounding 45 miles per hour! Ultimately the grade of steel is not only determined by the speed but on the car capacity as well. The heavier the weight the car can lift, the higher strength required.
2. Governor Ropes – A governor is part of elevator safety that you will find in the hoistway or overhead space. The second that an elevator car starts falling or even rising too fast, the governor triggers the safety mounted on the car frame and brings the car to a halt. The governor rope runs over the governor sheave and down to the elevator car and is attached to the safety trip mechanism. The governor rope continues all the way down to the pit and runs under a sheave down there and then makes the journey back to the governor. This governor rope arrangement forms a continuous loop while the elevator moves up and down the hoistway. If the car starts going too fast, centrifugal force pushes flyweights outward in the governor against the spring. In simplistic terms it tells the brakes to kick in and stops the car from falling or rising too quickly. As this entire safety system relies on the governor rope, it is very important that it is reliable and in great working condition.
3. Compensating Ropes – Turns out that all of the cable or rope to make an elevator car go up and down is really heavy. This is especially true for really tall buildings. Think about this; a standard one inch elevator cable can weigh 1.85 pounds per foot. As elevator cable makes several trips up and down the hoistway, this weight can really add up. So compensating ropes [compensate" for all the weight of the hoisting ropes on the car or counterweight side. Probably any elevator that exceeds 100′ of travel needs these ropes that are connected to the sling that holds the car and the counterweight frame.
The most important thing about any elevator rope is that they must be in good operating condition at all times. This means inspected often. The technician when performing routine checks doesn`t just look up the hoistway, nod their head and move on; they must check the ropes closely for proper tension, any wear patterns, the diameter of the rope, any rusting, pitting or breaks in strands, the sheaves, proper lubrication and connections.
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