Steel Detailing | Precast Detailing | Estimation

Tag: precast

  • ARCH STAIR PLAN DETAILS AND DRAWING STUDY

    1. Stair or fire stair drawings are used to find the stair landing RL, landing slab set-out (X-axis distance), fire penetrations and stair pressurization riser details.
      (Refer Fig .01 & 02)
    2. This drawing package are provided by architect separately in arch consultant drawings.
    3. The main things for this drawing are to take the value of stair landing RL’s, Door and opening sizes.
    4. If any mismatch with consultant arch drawing, we have to raise RFI (Request for information) and confirm it. (Most of the cases we need to follow as per stair drawing package only. If we need to raise RFI (Request for information), make sure and cross check issuing date & other references from drawings).
    5. Stair Landing & its mid landing RL’s will be taken from Architect Stair section drawings. If they not provided, then we have to check those RL’s in arch concrete plans.

    ARCHITECTURAL STAIR PLAN (Fig .01)

    ARCHITECTURAL STAIR ELEVATION SECTION (Fig .02)

  • ARCH ELEVATION DETAILS AND DRAWING STUDY

    1. For Architecture elevation, mainly we used for door/window openings height and its location details. (If any other service drawings available means we have to consider that too).
    2. This elevation helps to take the FFL/SSL value of each level.
    3. It’s showing also the RL of parapet and roof level walls.
    4. For patterns, grooves and other elevation design details will be shown on architectural elevation.
    5. The different types of panels finish also shown on elevation where it’s required.
    6. They given all the side of elevation and section views for overall building profile appearance.
    7. It also shows the slab profile appearance and it’s RL’s. (Like floor slab, ramp, stair landing, and etc.,)
    8. Some cases, the arch core elevations also provided separately for stair and lift. It’s shown the details like door and window set-out, fire penetration set-out, landing slab RL and etc.

    Sample Arch core elevation (Fig.01)

    Sample Arch elevation (Fig.02)

  • THE USAGE OF NEAR FACE(NF) AND FAR FACE(FF) INDICATION ON SHOP DRAWINGS

    Near face (NF): Near face is a front view of the precast wall.

    Far Face (FF): Far face is an outside view or trowel face or table face of the precast wall.

    • Near face and Far face indication playing a major role on shop drawings to identify the component placing for factory people while manufacturing panel. (Refer Fig.02)
    • At initial stage we draw the panel footprint on marking plan and fix the panel view based on where the panel comes like inside or outside of the building.
    • In marking plan, we viewing the panels both inside and outside of the building because to achieve architect and structural aspects or requirements and to avoid some manufacturing difficulties.
    • The below mentioned details are used to fix the views for precast panels from marking plan.1. To View from inside of the building:
    • Good table finish will be on Far face.
    • Grooves, patterns, different profile design comes at outside of the building, so it will easy to assign profiles on far face of the panel and it will be on table face on factory. (Refer Fig.03 & 05)
    • For upstand or corbel to be comes at near face of the precast panels to avoid manufacturing difficulties.
    • If any bars connecting to in-situ at near face, we also view the panel from inside.2. To View from outside of the building:
    • For basement level panels no need trowel finish or good table finish on far face of the panel (Outside of the building). In this case we looking the panels from outside of the panel.
    • If panel have upstand or corbel profiles at outside of the buildings, we need to view the panel from outside to avoid manufacturing difficulties on factory. (Refer Fig.01)
    • In few cases, building inside is fully balcony and outside side is partially inside of the building. So, this kind of scenario we viewing the panel from outside of the building due to panel finish. (Refer Fig.04)

    General:

    • For multi-storied buildings, we follow the same elevation number for same set-out from lower level to above levels.
    • The starting level of panels we will fix viewing direction as per current level architectural and structural aspects.
    • Some cases the lower-level panels come at inside of the building and above level panels comes at outside of the building. In this case we viewing the panels same as per lower levels but we flipped the above level panels for manufacturing purpose.

    Advantages:

    • Drawing study is easy for factory people.
    • It will reduce the time delay of manufacturing the panels.
    • It will also avoid the manufacturing difficulties and Errors.

    Fig.01

    Fig.02

    Fig.03

    Fig.04

    Fig.05

  • RIGGING DIAGRAM AND IT’S USES

    • The rigging detailed diagrams are shown on shop drawings. (Ref Fig.01,02 & 03)
    • The rigging diagrams are designed based on the precast panel profiles.
    • It is indicating the lifting point position of precast panels for both factory and site.
    • Erection engineer will be approved the rigging diagram details.
    • The site people are preplanning to lifting the precast panels for erection.
    • It is indicating the demolding lifting points. So, the factory people will aware while lifting the panels on factory.
    • It is designed to distribute loads equally between all anchors in precast components such as walls, beams or flat slabs and etc.
    • It is also used for loading and unloading the panel while transportation.
    • The lifting accessories may be in the form of cables, hooks and etc.
    • Many accidents and failures will be avoided with the help of rigging diagram.
    • The time delay of the lifting to be reduced.

    (SAMPLE RIGGING DIAGRAMS FOR REFERENCE)

  • STRONGBACK AND TYPES

    Normally we are using the strongback in window, Door opening, uneven profile and panel handling purpose. It’s used to avoid the panel breakup, crack and damage during the panel lifting from table, Transportation (Loading & Unloading) and Panel erection on site. We are using three types strongback based on the required strength.

    1. PFC Strong back.
    First is the PFC member which can be bolted to the face or welded to plates on edge.

    2. RHS (Right hand side) Strongback.

    Second is the New and preferred RHS which is bolted to the panel face.

    3. Elbow Strongback.
    Third is the Elbow strongback which is bolted to the panel face and hangs over one edge.

    PFC and RHS Strongback used in SHOP DRAWING.

    Strongback Photos reference for PRECAST PANEL.

  • VIBRATING TABLE FOR PRECAST FABRICATION

    • Vibrating table using for compacting and consolidating the stiff and harsh mixes in precast structures on factory or yards.
    • While using this vibrator the concrete will be spreads equally at all corners of the precast structure in mold.
    • It will help to improve the strength and quality of precast concrete structure.
    • The void or bubble formation will be avoided.
    • So, the cracks formation also to be reduced.
    • It will reduce the man power.
    • The fabrication time is less.

    Fig.01 (Vibrating table)

  • VARIOUS SPANDREL PROFILES

    • Spandrel profiles are designed based on architectural aspects on Elevation purpose.
    • When doing this kind of profiles, it’s challenging and more interesting to achieve.
    • And also, it will help to improve our drawing knowledge and skill.
    • We handled and come across different types of precast spandrel profiles as per below,
    1. Spandrel with straight profile
    2. Spandrel with curve profile
    3. Spandrel with curve & triangle profile
    4. Spandrel with L shaped profile
    5. Spandrel with U shaped profile
    6. Spandrel with V shaped profile
    7. Beam type spandrel1. Spandrel with straight profile (Ref. Fig.01)

    Fig.01

    2. Spandrel with curve profile (Ref. Fig.02)

    Fig.02

    3. Spandrel with curve & triangle profile (Ref. Fig.03)


    Fig.03

    4. Spandrel with L shaped profile (Ref. Fig.04)

    Fig.04

    5. Spandrel with U shaped profile (Ref. Fig.05)

    Fig.05

    6. Spandrel with V shaped profile (Ref. Fig.06)

    Fig.06

    7. Beam type spandrel (Ref. Fig.07)

    Fig.07

  • PURPOSE OF SPANDREL OVER ON MARKING PLAN

    • When preparing marking plans, we need to show all spandrels set-outs on the plan layout that are fixing into the slab over. (Refer Fig.01 & 02)
    • It will help to find out which spandrel comes at level above.
    • While scheduling the current level panels, mean time it will helps to scheduling the above level spandrels.
    • And, it will help to manufacturing and erecting the spandrels with lower-level panels at same time.
    • For site crews, they also aware when pouring slab and erecting panel sequence without any time delay on site with reference marking plan.
    • It will reduce time consumption to plan for both manufacturing and erecting panels.
      Fig. 01 (Snap for Reference Marking Plan)

    Fig. 02 (Snap for Reference Elevation)

  • CONSIDERATION OF PRECAST LID SHOP DWGS

    The purpose of LID panel:

    LID panels are most commonly used for covering up the openings on building roof areas and also some inner part of the building where the precast slab is required. It can be seen in locations like lifts, stairs, water tanks, etc.

    LID PANEL ON LIFT

    LID PANEL ON STAIR

    Manufacturing consideration of LID panels:

    • Viewing direction of the lid panel is either plan view or view from below. Depending on consideration of manufacturing difficulties and near face finish and different profile requirements, it may change as vice-versa.
    • If lifting eye/ hook is projecting outside of lid means, we have to view the face with lifting eye as near face for manufacturing purposes. (Refer lifting hook/eye elevation view)
    • In lift lid, lifting hook/ lifting eye needs to be provided if it needs to be cast in the lid. Lifting hook detail normally given in lift drawing. (Refer lifting hook/eye placement plan view)
    • We can provide face lifters and either top or side lifters used for erection, lifting off table and transportation purposes.
    • Face lifters were used for installation of the lid on site. Whether its need to be near face or Far face is decided by viewing direction.
    • Bottom connection of lid most likely by grout tube to its lower panel or In-situ.

    LIFTING HOOK/EYE ELEVATION VIEW

    LIFTING HOOK/EYE PLACEMENT PLAN VIEw