Structural Steel Erection

Structural Steel erection

Setup construction logistics for preliminary Structural Steel erection survey

a) Labour license

B) Car Policy & Workmen Compensation policy by Willus

C) PF and ESI formalities by Willus Infra Certified Builder, facilities at site to be provided by client.

d) Approach roads to yard and buildings from the road

e) 7,000 – 10,000sqm. Open space for storage of materials, with compacted level floor inside and around the building for safe movement of Cranes & Hydras.

f) 100 sqm of area for site office and workers’ rest rooms.

Introduction

The purpose of this method statement is to describe and communicate the procedures, the safety measures and quality requirements for the above-mentioned work. The supervisor must read this method statement to the site personnel who will be undertaking this work.

To ensure complete understanding, the contents of this method statement shall be translated to the languages known to the workmen, while being read out to them.

C ) Sequence Of Operation

Note: – Erection to the structural building must start from braced bay.

STEP-1

To the main column attach flange brace angle, bracket and clips. Erect the main column in the wind-braced bay. Immediately tighten the anchor bolts and after fixing the main columns with nut and lock nut. Plumb the column, after plumbing, if there is any gap between the bottom of the base plate and top of the R.C.C. Column, place the M.S. shim plates. After checking the plumb retighten the nut and temporary bracing (Guy rope should be M.S. wire rope of minimum dia 16 mm) is placed.

Note: The crane should be released only after placing the temporary Bracing (Guy ropes) and full tighten of bolt.

STEP-2

Same procedure in step-1 has to be followed for erecting the second adjacent column. Fix immediately the eave strut between the two columns. Install the grits and flange braces.

Connect both of the bracing with hill side washer and nuts. Once placed, the braced rod should be tightened fully.

The hill side washer assembly along with the wall bracing is shown in full details in the figure -2

Note: Same procedure has to be followed in opposite grid for erecting column and bracing.

STEP-3

Bolts in place as many clips and flange braces as possible before rising rafter to reduce erection time, as it easier to assemble these pieces on ground than it is to do in the air.

Install and tighten all frame connection bolts, as each grid frame assembled.

Check the primary frame drawing for flange brace location, attach the flange brace to the roof rafter assembly while on the ground to one side, and attach flange brace to opposite side when rafter assembly is raised into the vertical position.

STEP-4

Raise the rafter place it with the help of cranes with proper guy ropes. At end of the rafter hold with temporary bracing from ground. It will help to connect the rafter with column connection at both ends. Refer

Hold rafter in place until it is securely bolted to the column, temporary bracing is installed to hold assembled ridge frame in place. The temporary bracing should be guy ropes (16mm dia M.S. steel minimum). The temporary bracing should be tensioned with R.C.C. column with 1-m turn-buckle.

The temporary bracing should be tightened with same tension on opposite sides.

STEP-5

Warning: At all the haunches (connection plate of rafter) temporary bracing must be installed.

Before erecting the second rafter third main column to be erected as per the procedure followed in step-1. After erecting third main column sequence rise the second rafter. Hold the rafter with crane in place until the section is bolted to columns.

ll purlins, flange braces and sag rod should be bolted in place.

Install roof brace rods with help of hill side washer and nuts. The brace rod should be tightened fully. Proceed to plumb and square (aligned) the braced bay place the temporary bracing at haunches.

No further erection is to proceed until the above mentioned 3rd & 4th steps are completed crane has to be released only after the completion of step 3 & 4.

After completion of alignment of brace bay, the gap between top of R.C.C. column and bottom of base plate should be grouted by a civil contractor using CONVEXTRA immediately (GP-2 non shrinkage grouting material). Note: The gap between the top of the R.C.C. column and bottom of base plate should not be more than 25mm.

STEP-6

To proceed with the erection of remaining frames in each braced bay shown in fig.-7 wherever the braced bay comes the erection of temporary bracing shall follow the procedures as in steps 3 and 4. After completion of sheeting only, temporary bracing can be removed.

STEP-7

The steps to be followed for placing the temporary bracing on ground system arrangement.

In long building where temporary bracing are required for quite long time temporary anchors of ISMB-150 or ISMB-200 are used.

The minimum length of ISMB used should be 2mts.

ISMB should be inserted in ground to a depth of 1.5 to 2 mts. by hammering.

The direction of insertion of ISMB is as shown in fig. below.

STEP-8

In the opposite side of rafter the ground rope is connected to the column in the building (as shown in figure – 8) in such a way that there is no obstruction in further erection.

Site :

1. Cordoned off work area at ground level

2. Display safety notices

3. Inspection of cranes & other lifting gear certificates.

4. Installation of suitable scaffolding wherever required

5. Providing shim plates on the column foundations ( max. 50mm – refer drawing) to level the column. Check the reference level / FFL of building

6. Checking of Anchor Bolts with reference to the Construction drawings prior to start of Erection.

7. Erection of columns in Braced Bay location: planning erection work from grid 1.

8 : Repeat the above process for grid 2, 3 and 10.

STEP-9

After completing the main frame erection of bracings will be done. Tight all the members using spanners and torque.

STEP-10

Align the building up to first bracing bay from grid 1 to 2 & 8 to 9

Step – 11 : For further erection follow the steps from 1st to 10th.

Step – 12 : Check the alignment, leveling and tightening of structure from grid 1 to 10.

Step – 13 : fix the rake angles in the side wall and end wall eave struts from grid 1 to 10 with valley gutter in both the side walls.

Step – 14 : Shift the sheets from storage yard to erection place as per approved drawings and start the roof and wall sheeting as per approved erection drawings.

Step – 15 : Start the roof sheeting and wall sheeting work from grid line 1 to 10 as per approved erection drawings and part marks given in the drawings.

Step – 16 : Shift the DSP material from material stock yard to erection place.

Step – 17 : Fix the DSPs as per approved drawings and part mark given in the drawings using suitable crane and rope pulley.

Step – 18 : Nuts & Bolts use the DSP with valley gutter and fix the supports in wall as per drawings.

Installation Double Skin In Roof

1. Liner sheet to be fixed on purlin same as per procedure of fixing of Hi-rib sheets in roof.

2. Fixing of liner sheet on purlin with respect to rib/valley to be followed as per drawing.

3. For location of screws refer installation drawing of particular project.

4. Insulation to be layed on liner sheet.

5. Sub-Girt to be fixed through screws on purlin line.

6. Top- Sheet (Hi-Rib, Klippon, SS-2000, and SL-1750) to be fixed on sub-girt as per the fitment rocedure of respective profile.

1. At the time of installing place the first sheet place the female end of sheet towards starting end and male end towards installation side.

2. Start screwing the sheets in first valley from starting end, one screw in each valley to be provided.

3. Place the female end of second sheet over preceding sheet and start screwing as mentioned in step 8.

4. In side lap, provide stitching screw at the rib between two girts.

5. Maintain minimum end lap of 125mm in case of Roofing / Cladding.

6. Continue placing & screwing the sheets to complete the cladding.

Note: – Clean the installed Hi-Rib sheet at the end of every day.

C ) Design Codes

Following are the main design codes generally used:

AISC: American institute of steel construction manual

AISI: American iron and steel institute specifications

MBMA: Metal building manufacturer’s code

ANS: American national standards institute specifications

ASCE: American society of civil engineers

UBC: Uniform building code

IS: Indian standards

D ) Design Criteria

DESIGN METHOD : Allowable stress design method is used as per the AISC specifications.

DEFLECTIONS : Unless otherwise specified, the deflections will go to MBMA, AISC criteria and standard industry practices.

PRIMARY FRAMING : Moment resisting frames with pinned or fixed bases.

SECONDARY FRAMING : Cold formed Z sections or C sections for purlins or girts designed as continuous beams spanning over rafters and columns with laps.

LONGITUDANAL STABILITY : Wind load on building end walls is transferred through roof purlins to braced bays and carried to the foundations through diagonal bracing.

DESIGN SOFTWARE : The latest software that is used for design is STAAD pro and mbs

DESIGN PROCESS : The frame data is assembled based on number of frame members, number of joints, number of degrees of freedom, the conditions of restraint and the elastic properties of the members. Based on this, the data is stored and member section properties are computed. The overall joint stiffness matrix is obtained based on the above frame data by summation of individual stiffness matrices considering all possible displacements. The load vector is then generated based on the loading data and the unknown displacements are obtained by inverting the overall joint stiffness matrix and multiplying with the load vector.

Validation process validation process differentiate major PEB companies to minor PEB companies .each design process is documented and validated by senior structural engineers to eliminate errors .

Detailing processwillus peb rely all detailing on 3D detailing process by using various advanced software which provides accurate detailing ,faster erection drawings and sequential dispatch process .

Structural steel erection is a critical aspect of many construction projects, and it requires careful planning, specialized equipment, and experienced professionals to ensure a safe and efficient process. Whether you are building a high-rise office tower, a manufacturing facility, or a bridge, the structural steel elements provide essential support and stability for the structure.

At Willus Infra, we have extensive experience in all aspects of structural steel erection, from initial planning and design to on-site installation and safety measures. Our team of professionals works closely with architects, engineers, and contractors to develop custom solutions that meet the specific needs of each project. We take into account factors such as site conditions, project timelines, and budget constraints to ensure a successful and timely completion.

One of the key factors in the success of any structural steel erection project is safety. The installation of heavy steel beams and columns requires specialized equipment, careful coordination, and strict adherence to safety protocols. At Willus Infra, we prioritize safety at all times, and our team undergoes rigorous training and certification to ensure they are equipped to handle all aspects of the job safely.

In addition to safety, efficiency is another critical factor in structural steel erection. By utilizing the latest technology and equipment, we can streamline the installation process, reducing costs and minimizing delays. Our experienced professionals work collaboratively to ensure that all aspects of the project are executed with the highest level of precision and accuracy, resulting in a high-quality finished product.

In conclusion, structural steel erection is a complex process that requires specialized expertise, equipment, and safety protocols. At Willus Infra, we have the experience, knowledge, and commitment to safety to ensure that your project is completed successfully and efficiently. Contact us today to learn more about our structural steel erection services and how we can help you achieve your project goals.

Structural Steel Erection

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