Department Of Civil Engineering Industrial Training Report
Support is used to take tensile force and every bit good as compressive force. Merely reinforcement bars carry tensile emphasis where compressive emphasis is carried by both reinforcement bars and concrete depending on the state of affairs carry burden. Normally steel saloon is used as support because it has adequate strength and steel bars are available at needed strength with just cost. In early yearss wooden saloon besides was used for this intent.
Concrete is weak in tenseness and strong in compaction. Reinforcement is provided to heighten the minute transporting capacity of construction. Tor steel bars are used as reinforcement stuff at our site. T-32, T-25, T-20, T-16 and T-10 bars which are imported from Singapoor, Malasiya and local merchandise besides and length of 6m and 12m, are used in our site.
The support is laid harmonizing to the structural drawings. After that the undermentioned cheques are done.
- Diameter & A ; type of bars
- No of stirrups
- No of links
- Lap length
- Starter bars if needed
- Cover blocks & A ; Covering
- Regular binding of bars together
- Placement of tenseness & A ; compaction bars
If there are any building articulations, they should be chipped and cleaned to bond decently.
7.1 INDICATION OF REINFORCEMENT IN DRAWING
Engineering drawings is a linguistic communication of communicating of inside informations. Therefore there is a criterion to bespeak support in pulling such as
6T16-101-8 B or T
This means that
‘6’- No of bars
‘T’ – Indicate tor steel
‘16’- Indicate the diameter of the saloon in millimeter
‘101’- Indicate the saloon grade
‘8’- Indicate the distance between two bars in inches
‘T’- Indicate the place of the saloon ( top saloon )
‘B’ – Indicate the place of the saloon ( bottom saloon )
7.2 BAR BENDING WORK
Bar bending is carried by machinery method and manual. For minor plants it was done manually with the aid of cutting lever. Skilled saloon benders are involved in this procedure. The saloon bender make his occupation harmonizing to saloon agenda which is given to him. It includes
a-? Size & A ; type of saloon
a-? Number of saloon
a-? Bending length
a-? Crank length place
- Shape of saloon
- Bar grade
- Name & A ; type of structural member
- Place & A ; Grids between those grids it is used
For reassigning the emphasis at the terminal of bars have to be welded or lapped at the terminal. The lap should non be less than the anchorage length. The minimal length of lap in tenseness and compaction is 45 times of diameter of the saloon. The types and Numberss of bars are planed earlier and cut. Sufficient Numberss of stirrups are besides made by saloon benders. Before puting the steel bars, they are cleaned good.
Lap length – 45 times of saloon diameter
Anchorage length – 40 times of saloon diameter
Stirrup anchorage length – 10 times of saloon diameter
Figure 7.1: Imbrication of Parallel barss
7.3 PLACING OF REINFORCEMENT
All support should be placed in right places as shown in pulling. It should non be allowed to travel when concreting. Screen blocks are used to put reinforcement bars with screen. Cover blocks are made up of 1:3 cement & A ; sand howitzers. Screen blocks are non removed after concreting and it is of import component. Its’ strength should non be less than to strength of concrete. Sizes of screen blocks vary harmonizing to the structural members. The screen block thickness of, slab is 25mm, beam, column, raise wall & A ; retaining wall are 30mm and shoring side & A ; H2O retaining constructions are 40mm.
When beams are bound it is kept out of the cavity of beam for the easy of work. First top bars of beam and stirrups are bound. Then other bars are inserted and bound. While support of beam is brought down after completing the work, really nicely it is acquire down without impacting the formwork.
Normally for all structural members lap is non allowed at a same degree for all bars. And alternate bars holding laps at a same degree. But columns have laps at a same degree because of troubles of binding of long bars and support is crowded at the junction of beam and column. Lap is avoided at critical place of tenseness and compaction.
7.4 SCHEDULE OF BARS
Agenda of bars gives the figure of bars required in each type for a support web. By holding saloon agenda following advantages can be achieved.
- Time salvaging in the support work
- Sum of steel required can be precisely calculated. So purchase in surplus or high conveyance cost can be avoided.
- Wasting of cut off pieces can be reduced give more efficiency as supports are expensive.
- Laps happening in tenseness part can be avoided.
- Bar benders can easy understand.
- Easy to manage at site.
While we make a saloon agenda we should cognize about the tenseness and compaction how to moving on the member. And lap should non be allowed to be in the tenseness part and critical compaction part besides. When we are making agenda for slab if portion of slab is finished for the balance work we take site measuring for needed length of support. The typical lap place for beam is shown below:
Figure: 7.2 TYPICAL LAP POSITION OF BEAM
Figure: 7.3 Typical END BAR OF BEAM
Slab is a sort of home base, which can transport tonss. Basically slabs are divided in to two types as one-way crossing slab and bipartisan spanning slab. Depending on the type of slab the sum of support, which placed to defy the minutes, is different. Most likely slabs are reinforced merely for tenseness and compaction is supported by concrete. Normally for center of slab support is placed at underside and border ( near the beam or supports ) of slab support is placed at top. But basement floor slab support is placed in resistance manner. Therefore center of slab support is at top and border ( around the beam ) of slab support is at underside. Between the top saloon and bottom saloon of the slab should be maintained while concreting it may be disturbed due to lade which is the burden of workers, instrument and concrete flow pipe. Overall support screen is checked by leveling instrument. To maintain the infinite between those two bars infinite saloon is used. Shape of infinite saloon is shown in theFigure: 7.4. Support for slab is shiwn inFigure: 7.9 & A ; Figure: 7.10.
Beam is the load-transferring member edifice, which transfer burden from slab to column. In the beams tenseness is supported by support and compaction is supported by concrete and support. In most occasions, center of beam undergoes drooping minute and beam nearby support undergoes hogging minute. For back uping the higher tenseness, extra tenseness bars are inserted at underside of in-between and top of border therefore nearby support. But basement floor support is in the resistance manner. For basement floor beams extra tenseness bars are inserted at top of in-between and underside of nearby heap caps. While bars are bound to the beam infinite between two bars should non be less than 1.5 times bar diameter. This minimal infinite is required for, to organize an adequate bonding between reinforcement concrete and to minimise the harm while impact burden is applied on the beam support take dynamic motion.
Column is the chief member to reassign the burden to foundation. Column is chiefly designed for transporting the compaction. But it is designed to back up the minute besides while sing the eccentricity and side force hence wind burden. In column compaction is carried by concrete and support. Column support is chiefly designed for support the compaction and little sum of tenseness that is caused by minute. For big size bars ( T 32, T25, etc. ) lap is held at same degree. Due to the handling job and if the lap is in the junction of column and beam concreting is really hard some clip huney homb may happen. Column typical lap is shown in the figure7.4. Probably most of columns supports are symmetrical about two axes. First when bars are bound verticalness of saloon is maintained.
Figure: 7.5 COLUMN TYPICAL REINFORCEMENT
7.8 Stair instance
Stair instance is same as slab support. Therefore tenseness reinforce is provided at underside and at the borders tenseness support is provided at top. Here in add-on to slab some tenseness support is provided junctions. Typical support is shown inFigure: 7.6.
Stirrup is chief component in back uping the shear force. If we consider column, stirrups are used for to hole the perpendicular saloon together. Due to lade column March majority in this state of affairs cracks may look in perpendicular way. Without go oning majority stirrups bound the column. In the beam, there is more chance to go on the shear failer because it transfer load horizontally. Beam is non a uninterrupted component that is the compound of cement, sand, sum and support. These elements are bound by bond, which may neglect in reassigning the shear emphasis. Of cause we use stirrups to transport out the shear emphasis for beams and columns. In our site stirrups are made by saloon bending machine. Stirrup form is shown in the figure7.6
Figure: 7.6Stirrup form
7.10 TYPICAL PILE CAP REINFORCEMENT
Pile cap support is shown inFigure: 7.11