Cubic Construction Company - ptyltd

22/04/2020

19/04/2020

06/01/2017

We do PLANS, INTERIOR ARCHITECTURE, CONSTRUCTION, PROJECT MANAGEMENT, BILL OF QUANTITIES, SPACE PLANNING & LAND SCAPING.

call us on 72436729/73575114

06/01/2017

FOR ALL UR CONSTRUCTION NEEDS PLEASE DONT HESITATE
TO GET A QUOTATION FROM US .

ENGINEERS FEARS NO OBSTACLE
WE CONSTRUCT YOUR BUILDING NEEDS AS U MAY PLEASE

06/01/2017

CALL US ON 73575114/ 72436729

ENGINEERS FEARS NO OBSTACLE
WE CONSTRUCT YOUR BUILDING NEEDS AS U MAY PLEASE

08/09/2016

hello. cubic construction need a person who is qualified in carpentry and joinery, tilling and plumbing. plz forward ur details to P O BOX 2146 GABS/CALL MR JOHN ON 72436729/73575114 OR JUST DROP UR DIALS WILL TALK

11/02/2015

10/02/2015

cubic construction company wish all a happy new year to all
and encorage all engineers and technicians to register with BIE&ERB

13/01/2015

SERVICES AND CORRESPONDING PRICES
1. BOQ PREPARATION
This will include reading the drawings and specifications for us to determine the quantity of work to be done on your project. A BOQ can then be used to invite contractors who are willing to work with you.
P3500.00

2. ESTIMATING/COSTING
This entails estimating the total cost of construction of the proposed building. Normally this stage is crucial as the estimate amount will cover the cost of buying materials and paying the successful contractor. This is basically the amount that you will have to source before any work can begin at site.
P3500.00

3. CLERK OF WORKS SERVICES
This service will include: construction inspection, quality inspection, quality control, site supervision, compliance, etc. we will always be there for you at site at all times to see that you project is delivered within the recommended standards.
3% of the total cost of construction

call 72436729/73575114
for any questions

15/12/2014

DESIGN OF FOOTINGS – IS-456 RECOMMENDATIONS:

GENERAL

1. In sloped or stepped footings, the effective cross – section in compression shall be limited by the area above the neutral plane, and the angle of slope or depth and location of steps shall be such that the design requirements are satisfied at every section. Sloped and stepped footings that are designed as a unit shall be constructed to assure action as a unit.

2. Thickness at the edge of footing: In reinforced and plain concrete footings, the thickness at edge shall be not less than 150 mm for footings on soils nor less than 300mm above the tops of files for footing on piles.

3. In the case of plain concrete pedestals, the angle clip_image001 between plane passing through the bottom edge of the pedestal and the corresponding junction edge of the column with pedestal and the horizontal plane (fig.1) shall be governed by the expression

DESIGN OF FOOTINGS – IS-456 RECOMMENDATIONS

Where clip_image003 = calculated maximum bearing pressure at the base of the pedestal in clip_image004

clip_image005= characteristic strength of concrete at 28 days in clip_image004[1].

Plain Concrete Pedestal

Fig.1

MOMENTS AND FORCES

1. In the case of footings on piles, computation for moments and shears may be based on assumption that the reaction from any pile is concentrated at the centre of the pile.

2. For the purpose of computing stress in footings which support a round or octagonal concrete column or pedestal, the face of the column or pedestal shall be taken as the side of a square inscribed within the perimeter of the round or octagonal column or pedestal.

3. Bending Moment:

i. The bending moment at any section shall be determined by passing through the section a vertical plane which extends completely across the footing and computing the moment of the forces acting over the entire area of the footing on one side of the said plane.

ii. The greatest bending moment to be used in design of an isolated concrete footing which supports a column, pedestal or wall, shall be the moment computed in the manner prescribed in (i) at section located as follows:

a. At the face of the column, pedestal or wall, for footings supporting a concrete column, pedestal or wall.

b. Half way between the center line and the edge of the wall, for footings under masonry walls, and

c. Half way between the face of the column or pedestal and the edge of the gusseted base, for footing under gusseted bases.

4. Shear and Bond

i. The shear strength of footings is governed by the more severe of the following two conditions:

a. The footings acting essentially as a wide beam, with a potential diagonal crack extending in a plane across the entire width, the critical section for this condition shall be assumed as a vertical section located from the face of the column, pedestal or wall at a distance equal to the effective depth of the footing in case of footings on soils and a distance equal to half the effective depth of footing for footing on piles.

b. Two way action of the footing, with potential diagonal cracking along the surface of truncated cone or pyramid around the concentrated load: in this case, the footing shall be designed for shear in accordance with appropriate provisions discussed below. (Fig.2)

Critical Section for Shear

Fig.2 – Critical Section for Shear

ii. In computing the external shear on any section through a footing supported on piles, the entire reaction from any pile of diameter clip_image009 whose centre is located clip_image009[1]/2 or more outside the section shall be assumed as producing shear on the section: the reaction from any pile whose centre is located clip_image009[2]/2 or more inside the section shall be assumed as producing no shear on the section. For intermediate portions of the pie centre, the portion of the pile reaction to be assumed as producing shear on the section shall be based on straight line interpolation between full value at clip_image009[3]/2 outside the section and zero value at clip_image009[4]/2 inside the section.

iii. The critical section for checking the development length in a footing shall be assumed at the same planes as described for bending moment in B(3) and also at all other vertical planes where abrupt changes of section occur. If the reinforcement is curtailed, the anchorage requirements should be checked.

iv. Thus according to the above provision, shear stress is to be checked for (i) one way action (i.e. beam shear) for which the governing section AB is at a distance d from the face of column or pedestal (fig.2(a)) and (ii) two way shear (i.e. punching shear), for which the governing section is along the perimeter ABCD situated at a distance d/2 from the face of the column or pedestal (fig.2(b)).

For the two way action, the calculated shear stress clip_image010should satisfy the following relation

clip_image011

Where DESIGN OF FOOTINGS – IS-456 RECOMMENDATIONS

clip_image013 but not greater than 1.0

clip_image014

Where b= short side of column, a= long side of column.

clip_image015clip_image004[2] in limit state design

clip_image016= net shear force acting on the perimeter

For the beam shear, the nominal shear stress across AB should satisfy the relation

clip_image017

Where clip_image018= the permissible shear stress for the grade of the concrete, corresponding to the reinforcement.

K= factor for slabs.

TENSILE REINFORCEMENT

The total tensile reinforcement at any section shall provide a moment of resistance at least equal to the bending moment on the section calculated in accordance with B(3). Total tensile reinforcement shall be distributed across the corresponding resisting section as given below:

i. In one way reinforced footing, the reinforcement shall be distributed uniformly across the full width of the footing.

ii. In two way reinforced square footing, the reinforcement extending in each direction shall be distributed uniformly across the full width of the footing.

iii. In two way reinforced rectangular footing, the reinforcement in long direction shall be distributed uniformly across the full width of the footing. For reinforcement in short direction, a central band equal to the width of the footing shall be marked along the length of the footing and portion of the reinforcement determined in accordance with the equation given below shall be uniformly distributed across the central band.

DESIGN OF FOOTINGS – IS-456 RECOMMENDATIONS

Where clip_image020is the ratio of the long side to the short side of the footing.

The remainder of the reinforcement shall be uniformly distributed in the outer potions of the footing.

TRANSFER OF LOAD AT THE BASE OF COLUMN

The compressive stress in concrete at the base of the column or pedestal shall be considered as being transferred by bearing to the top of the supporting pedestal or footing. The bearing pressure (clip_image021) on the loaded area shall not exceed the permissible bearing stress in direction compression multiplied by a value equal to clip_image022but not greater than 2.

Where clip_image023 = supporting are for bearing of footing, which in sloped or stepped footing may be taken as the area of the lower base of the largest frustrum of a pyramid or cone contained wholly within the footing and having for its upper base, the area actually loaded and having side slope of one vertical to two horizontal and

clip_image024= loaded area at the column base.

For limit state method of design , the permissible bearing stress shall be clip_image025.

Thus, clip_image026

The actual bearing pressure clip_image021[1]= column load divided by the area of column at the base.

Thus, clip_image027 where ‘a’ and ‘b’ are the sides of the column.

1. Where the permissible bearing stress on the concrete in the supporting or supported member would be exceeded, reinforcement shall be provided for developing excess force, either by extending the longitudinal bars into the supporting members or by dowels (see 3 below).

2. Where transfer of force is accomplished by reinforcement, the development length of the reinforcement shall be sufficient to transfer the compression or tension to the supporting member.

3. Extended longitudinal reinforcement or dowels of at least 0.5 percent of the cross sectional area of the supported column or pedestal and a maximum of four bars shall be provided. Where the dowels are used, their diameter shall not exceed the diameter of the column bars by more than 3mm.

4. Column bars of diameter lager than 36 mm, in compression only can be dowelled at the footings with bars of smaller size of the necessary area. The dowel shall extend into the column, a distance equal to the development length of the column bar and into the footing, a distance equal to the development length of the dowel.

NOMINAL COVER

For footings, minimum nominal cover shall be 50mm.

NOMINAL REINFORCEMENT

The nominal reinforcement for concrete sections of thickness greater than 1m shall be 360 clip_image028 per meter length in each direction on each face. This provision does not supercede the requirement of minimum tensile reinforcement based on the depth of the section.

15/12/2014

Quality management systems in concrete construction should be the essential part of the construction project. Quality management system is nothing but a set of documents that provides detailed guidelines on quality management of concrete construction. It establishes systematic way of setting quality processes and roles and responsibilities and improving quality.

Need of quality management system:

Quality of concrete construction depends on many factors. From the selection of construction materials to the curing of the structural member, each and every step must be carried to maintain the quality requirement of the project. Any deviation from the required quality may result in failure of the structure or may impose penalty on the contractor for not maintaining the quality.

Quality of concrete construction includes steps for maintaining the required strength of concrete within the deviation permitted and construction of a durable structure. A concrete member may have the required strength just after the construction, but if it not compacted well, the surface may be porous, and corrosion of reinforcement starts which reduces the life span of the structure. So, durability should also be an important part of the construction management system.

Concrete Quality Management System

The documents prepared for quality management of concrete construction should have step by step procedure for all the activities to be carried out during concrete construction. The standard document should also contain testing procedures for construction materials such as cement, sand, coarse aggregates and admixtures if required. The testing procedures for concrete during construction such as workability test.

The quality management system should have checklist for formwork, reinforcement, embedments, etc during construction stage.

Benefits of Concrete Quality Management Systems:

1. Quality of construction activities will be tracked by quality management documents and becomes a record for future reference.

2. Quality management system improves perception of customers towards company due to credible quality personnel and quality practices.

3. Good quality construction reduces the wastage of materials, smooth function of the team and keeps the construction cost within the limit.

4. It improve job-site concrete handling, curing, sampling and testing procedures to reduce potential liability to the company.

5. Minimize cost of repair and maintenance of the structure after construction due to quality works.

5. It opens the area of improvement for quality construction rationally based on the documents from previous projects.

15/12/2014

Techniques to Repair and Restore Strength of Structural Members:

1. Repair of Small cracks:

Cracks of small openings i.e. 0.075mm can be repaired by pressure injection of epoxy. The procedure for pressure injection is given below:

Clean the external surface thoroughly and make free from dust particles. Place the plastic ports along the crack surface on both sides of the member and secure it in place with an epoxy sealant. The centre to centre spacing of these ports may be approximately equal to the thickness of the element. When the sealant has cured, inject the epoxy resin beginning the lowest part of the crack at one part at a time in case of vertical or at one end of the crack in case it is horizontal structural member.

The injection of resin is continued till it starts to flow from the opposite side of the structural member at the corresponding port, or from the adjacent port on the same side of the member. Close the injection port at this stage, an continue injecting the epoxy resins at the next port and repeat the same procedure as discussed above.

It should be remembered that the distance between ports should be more closely spaced as the cracks gets smaller and pressure of injection should be higher. This is to ensure that epoxy is injected throughout the length of the crack. This technique is used for all types of structural elements- beams, columns, walls and floor units in masonry as well as concrete structures to restore the original strength.

2. Repair of Large cracks and crushed concrete:

Repair of large cracks (more than 6mm) and crushed concrete or masonry structural elements, following procedure may be followed:

Remove the loose material and clean the surface of the concrete cracks, and replace the crushed concrete or masonry with expansive cement mortar , quick setting cement or gypsum cement mortar.
Provide shear reinforcements wherever necessary in the region of repairs. Cover this reinforcement with mortar. This will provide strength as well as protection to the reinforcement.
For severely damaged concrete or masonry members, the complete damaged portion is removed and replaced with shear reinforcement (where necessary) and masonry as explained above.
In case walls and floor diaphragms are damaged, its repair can be done with ferro-cement. Steel mesh is provided on outside surface and fixed on the damaged surface by means of nailing or bolting and then covered with plaster or micro-concrete.

3. Repair of Fractured, excessively yielded and buckled structural member:

When a structural member is buckled or excessively yielded, its reinforcement would have buckled or elongated or excessively yielded. In such case, the structural member can be repaired by removing the damaged concrete portion and cutting the yielded portion of the reinforcement. Then new reinforcement bars are used as replacement and welded to the old portion of the reinforcement steel. Damaged concrete is replaced with fresh concrete. During this procedure, it may be necessary to provide temporary supports to the structures, as splicing of reinforcement without supports may collapse the structure.

If required, also provide additional reinforcement steels and shear reinforcements to prevent future buckling of structural members.

4. Repair of Fractured wooden members and joints:

Wooden structural members can be easily repaired. To restore the original strength structural members made of wood such as beams, columns, struts and ties can be done by splicing additional material. The weathered or rotten wood should first be removed. Nails, wood screws or steel bolts will be most convenient as connectors. It will be advisable to use straps to cover all such splices and joints so as to keep them tight and stiff.