This document summarizes a seminar on top down construction presented at Ajay Kumar Garg Engineering College. The seminar introduced top down construction as an alternative to conventional bottom-up construction for large projects with time or space constraints. It described the methodology of top down construction including installing diaphragm walls and piles, excavating below roof slabs with structural supports, and progressively excavating and constructing underground levels while building above-ground levels simultaneously. Advantages of top down construction are shortened timelines from simultaneous work, more early operational space, and suitability for tall urban buildings. Disadvantages include higher costs and requiring skilled supervision.

1. SEMINAR
ON
TOP DOWN CONSTRUCTTION
AT
AJAY KUMAR GARG ENGG. COLLAGE
BY CE-1
ANUPAM TIWARI ROLL NO. 1502700903
10 November 2017

2. INTRODUCTION
• Conventionally, buildings with underground basements
are built by Bottom-up method
• But it is not feasible for the gigantic projects with
limited construction time and/or with space and other
site constraints.

3. INTRODUCTION
• The Top-Down construction method enables the
superstructure and the underground structure to be
built simultaneously.
• This technique can reduce construction time
significantly.

4. METHODOLOGY
• Installation of Diaphragm wall.
• Installation Wall Barrette Piles.
• Excavation of Soil just below roof slab.
• Provide Structural strut to support diaphragm wall
• Exposed Coupler bars/Dowel bars from Diaphragm.

5. METHODOLOGY
• R.C.C. slab to be cast with suitable size opening for further
construction.
• After Casting slab, excavation to continued through opening.
• Excavation to be continued till base slab level.
• MaterialTopDown Final.pdf

6. 1. Installation of
Diaphragm wall
2. Excavation &
Installation of Steel
Strut

7. 3. Construction of
Underground
Structure
4. Next level of
Construction of
Underground
Structure

8. 5. Construction of
side walls &
Remove the Strut
6. Backfilling &
Reinstatement

20. ADVANTAGES
• The shortened construction period due to simultaneous
construction.
• More operational space gained from advanced construction of
floor slabs.
• It is highly suitable for construction for tall buildings with deep
basements to be constructed in urban areas.
• These can be installed in close proximity to existing structure
with minimal loss of support to existing foundations

21. DISADVANTAGES
• Higher cost.
• The lateral displacement of retaining wall or ground settlement
may possible.
• The construction quality may influence.
• It requires highly skilled supervision and labour force.

22. Source
• Top Down and Diaphragm wall
• Methodolgy of Top Down Construction
https://www.youtube.com/watch?v=e2gCBVq7R6Q
• http://nptel.ac.in/
• file:///E:/PRESENTATION%20for%20SAMINAR/Material/TOP%20DO
WN%20CONSTRUCTION%20(1).pdf
• www.diaphragmwallconstruction.com

23. Thank You!