Explanation: As per clause 13.2 of IS 456: 2000, the maximum permissible free fall of concrete to avoid segregation may be taken as 1.5 m or 150 cm. Segregation: Segregation can be defined as the separation of the constituent materials of concrete.
below 1.5 mtr...if the pouring is above 1.5mtr than concrete will segregate n also slurry loss. The ACI code I suppose does not really specify that but as per practice 1.5m is used as the maximum freefall height of concrete. It should be 1.5 mtrs otherwise it will segregate.
Pouring from height can dislocate the reinforcement as well due to more weight force ( mgh = weight of concrete x height)
Column formwork: In building, floor height is normally kept 10 feet. If the slab has beam then we have to pour concrete up to beam bottom level. Suppose, beam height specified in drawing is 1′-6″. So, the casting height of our column will be 8′-6″.
Each lift should fill a third of the volume. Height of concrete for first lift should be 2-5/8", and second lift should be 6-1/8". After the last rod, screed the material off the top (an 1/8" excess concrete above top of mold is optimum) and wipe any concrete from around the base of the cone.
A high strength may cause the concrete to be more prone to cracking (serviceability concern). Un-designed high strength may be detrimental in seismic design where you want members to fail in certain locations and in certain modes.
Home elevators provide access to multiple floors. Mostascend up to 50 feet, which means they can travel up to five floors. Most home elevators feature two stops, but you can add up to six depending on the model and travel distance required.
When pouring concrete into tall walls or columns, it is recommended that the concrete be placed in layers. These layers should be anywhere between 12” to 36” thick. The pour should include an interval of time between each layer to allow for settling and pressure distribution.
The distance between two reinforced columns ranges between 3-4 m for small buildings and 6-9 m for sizable facilities where large columns and free spaces are required. For ordinary structures, a distance of 5 m is appropriate, and the maximum span is 7.5, while the minimum is 2.5 m.
Column Starter Construction:
Column starter marking is the process of casting the first 50 to 100 mm height of column for the alignment of rest of the column. To construct the column starter, shutters are made to the size of the column and the height of shutter should be normally 75 to 100 mm.
Concrete @ your Fingertips
Typically areas of 1,000 to 2,000 m² or more of slab can be laid each day with this equipment. Large area pours can be manually laid using superplasticised, self-compacting concrete.
Yes, you can pour fresh concrete over existing concrete. As long as your concrete is in mint condition, this task is doable. If you decide to pour a new mixture over an old slab, be sure it is at least 2 inches thick.
Plan to pour concrete before 10 a.m. or after 8 p.m. in order to avoid the hottest part of the day. If you are concerned about the temperature while working on a summer project, consider pouring concrete at night to give the mixture the best chance to harden and cure before the sun comes up.
How thin can you pour concrete over concrete? Your new layer needs to be at least 2 inches thick. If it's any thinner than that, it'll easily crack under pressure and won't adequately bond to your surface.
You can put new concrete over old concrete. However, unresolved issues with your old concrete, such as cracks or frost heaves, will carry over to your new concrete if not taken care of. In addition, you must pour it at least 2 inches thick.
Most specifications for retail or commercial concrete slabs specify 4 to 6 inches of thickness. Owners and contractors have historically disputed whether a poured slab meets a specification because of its thickness.
The two-way flat plate slab is simply a slab of uniform thickness directly supported on columns, and it is generally suitable for relatively light loads. Two-way flat plates can be used for span up to 8m using reinforced concrete and up to 11m with the post-tensioned system.
The one-way slab is economical up to a span of 3.6 meters. Whereas the two-way slab is economical for the panel sizes up to 6m × 6m. In one-way slab quantity of steel is less.
The minimum required size of the column should be 9"х 9". 2. When you provide a 9"х 9" column to the building, the distance between the two columns should be ≤ 4m or 13'.
Long story short, yes you can pour concrete over dirt.
Fact: Fresh wet concrete does not normally bond well to existing dry concrete.
Damp proofing for extensions
These days, damp proof membranes are required in the construction of all new buildings to prevent rising damp. These strong and highly durable Polyethylene 1200 Gauge DPMs are sandwiched between the hard core and concrete slab to form an impermeable layer.
There are several heights to choose from, ranging from 1.5 to 6 inches. The height of your lift kit depends on your lifestyle and driving habits. If you are off-roading on uneven terrain, consider a kit closer to 6 inches that gives your vehicle higher ground clearance.
The JLG 1850SJ Ultra Boom Lift is “the world's largest self-propelled boom lift, providing nearly 3 million cubic feet of reachable space.
For most office buildings, the average maximum speed is about 21 feet per second (5.8 m/s).