Duration of the Multistory Building

Ball park estimate: (Thats how critical path shud flow through)

- Mobilization & submittals -> 12 weeks (Incld approvals & NOC’s)
- Sub-Structure works -> 15 weeks (Incld raft & approvals)
- Struct. Conc. works -> 25 weeks
(17 days each floor for basement & ground + 14 days cycle for remaining floors)
- Cladding Works -> To complete 8 weeks after structural works are over.
- MEP remaining Works -> 6 weeks (After cladding completion)
- Remaining finishing works -> 8 weeks After substantial completion of MEP works
- Testing & Commissioning -> 10 weeks
- Punch List & H/o -> 2 weeks

However, a lot depends on drawings & ur project specifications and above estimates are for a typ. building project in gulf.

Dear Mukanda,

Start with:

Foundation 60 days
Skeleton: 30 days for each floor

Finishes & Electromechanical can start after completion of 1st floor up to the end of the project.

Testing and completion can start at Month 18-21 from the Bottom up.

You still have to consider the landscape works as well. Maybe from month 17-21.

Hope that the information helps.

With kind regards,

Samer

Hi All

I am amazed that you can give such precise durations when you do not know anything about the project.

Is it steel frame or insitu concrete?

What is the cladding?

What is it for - Hotel - Housing - Office - Hospital - Pigeon Coop whatever?

Best regards

Mike Testro.

Dear Mike,

Most of the project that are this type have a reinforced concrete skeleton.

You are correct with your questions, but if you want to finish in 21 Months, then most probably you have a conventional project.

I think that the best thing to do is to ask the originator for more details in order for us to give him better estimates.

With kind regards,

Samer

Surface area of the project?
usage of construction joints?
where will equipment/material be stored?
How many Tower Cranes?
Have u calculated slab construction cycles? Post tensioned slabs?
Any constraints related to resources/formwork?
Rough finish RC concrete?Architectural concrete?
Calendar Constraints?can you work on sundays? overtime? on holidays?

Dear Mukunda,

I think that if you answer the questions by PP members, you can get your Plan with durations within 2 days max.

With kind regards,

Samer

Dear all
Thanks for the advise..

furthermore building is concrete skeletion building, external surface is covered with plastering, painting...there is no significant cladding.
surface area 92*25 Sm(Tota area)
slab is divided into 3 portions (2 expansion joints)
slab cycle is 15 days
one Tower crane.
No constraints to the manpower resources
constraints is to the Formwork system.....

Dear mukunda,

Can you please answer the questions raised until now by PP members, the area, etc.

With kind regards,

Samer

& upto the GF slab contains retaining wall

Hi Mukunda
You said
slab cycle is 15 days
How many levels are back propped - what is the final curing time?
It sounds like there is masonry walls - are all floors the same footprint or do the upper floors get smaller?

And please - what is the building to be used as?

Best regards

Mike Testro.

Mike
only one level is back proped..
Building is full of Masonry walls......
Yah all floors same foot print, except 2 Basement....
GF + FF shopping malll
2F service floor
remaining floors are for resedential purpose,,,,,,

Dear Mukunda,

Here is a brief estimate for your review:

1. Excavation : say 100x25= 2500 x 1.4 factor = 3500 x 2 basement 3.5m + Raft height 1m = ~40,000 / 500-1000m3/ day = 60-80 days

If your excavation can hold itself and you do not need to do any shoring, then you can start with the Raft.

2. Cleaning and compaction before blinding: say 3 days.

3. Blinding 92*25*.1 = 230m3 say you can finish it within 1 week with the required shuttering on the sides.

4. Insulation & Insulation protection below the raft =2300m2/ (100m2/day/person) = 23 man days, say 4 persons = 6 days

5. Raft Reinforcement: Lets say the raft is also in three section and two expansion joints (or not), you can finish it within 30 days if you have enough resources.

6. Raft Side Shutter (if needed) within the same period

7. Basement Walls and vertical members.
7.a Insulation of Basement walls from outside: you need to determine what is the method. If you can build block walls, that is perfect, otherwise, you have an option of shuttering and pouring blinding for the walls as well. This will take some time. The third option is harder, and I will leave it until later until you reject the first two options.
So block building 240m perimeter x 4meter height = say 1000m2 / 10m2/day/person = 100 man days, say you have 10 masons = 10 days
7.b Insulation & Insulation protection of walls = 1000m2 /(50m2/day/person because of scaffolding, etc) = 20 man days / 4 persons = say 5 days because
7.c Reinforcement of walls & Shuttering: 90 meter side you need 7 days, and the 25 meters side you can finish it in 3 days (12 steel fixers and 12 helpers), so you need around 21 days for reinforcement of walls for basement (this is conservative)
7.d Shuttering of Walls: the activity can start 2-3 days after the steel reinforcement and can finish 2-3 days after the steel reinforcement;
7.e Removal of shutter; this needs 2-3 days after casting.
so you can say 30 days after raft casting the Basement walls will be ready with the columns in the middles and any shear walls as well.

8. Slab cycle: you stated that it is 15 days.

So you have until now

Excavation = 60 days
Raft = 30 days
B2 Walls = 45 days
B2 Slab = 15 days
B1 Walls = 45 days
B1 Slab = 15 days
GF vertical Members= 15 days
GF Slab = 15 days

So you have 240days / 30 = 8 month until you reach the GF and then you need a month per floor = 1*9 = 9 months. So total 17 floors until you complete the skeleton*1.05 float = say 18 months.

You can start the MEP & the Finishes at month 9 after cleaning the basements.

Let us know your feedback according to the Site Conditions and Contract requirement and we will add the required modifications to the Plan.

With kind regards,

Samer

Dear Mukunda,

- You mentioned Formwork constraints... Could you be more specific?
- You mentioned Shopping Mall.. Which means to me that some floors are actually higher then the usual.
How are you planning to handle Vertical Elements in those high floors? Cast vertical elements in 2 different stages or 1?
- I am not sure that one tower crane will be enough even if its a 50 m Tower Crane. Tower Crane have a maximum capacity too.
- Try to use the reshoring method instead of the backpropping method. Backpropping might result in developping overloading especially on lower level interconnected slab.


@Samer: The term construction cycle is not about the duration of slab formwork/rebar/casting but rather the whole construction cycle made of 4 phases:(according to ACI 347.2R) and I Quote:
"In a typical construction cycle for a multistory cast-inplace concrete building where both shores and reshores are used, there are four construction phases:
• Phase 1—Installation of the shores and formwork
followed by the casting of the floor slab;
• Phase 2—Removal of the shores and formwork allowing
the slab to deflect and carry its own weight;
• Phase 3—Removal of reshores at the lowest interconnected
level; and
• Phase 4—Placement of reshores in the story from which
the shores and forms were removed. The reshores are
placed snugly without initially carrying any load.
If only shores are used, then the third and fourth phases are eliminated"

Dear Roland,

This is very valuable, thank you. What else do you recommend from ACI.

With kind regards,

Samer

If most of the projects you are involved in refer to ACI codes and because you’re a civil engineer I recommend that you become a member of ACI. You’ll have the ability to have the whole codes for a good price as well as a wealth of information and connections.
There are almost 180 ACI by the way. Could I dare say I recommend them all? :D
regards,

Roland

Dear Roland,

Thank you. I am already a member. The issue is recommending what you saw pertinent to your work.

With kind regards,

Samer

Hello Samer !

My work is not really limited to a particular subject . Not necessarily a good thing. But I constantly find myself trying to fill gaps left by others whether in planning or engineering or management related subjects.

As far as ACI codes go I do tend to use a considerable number of them.
I use the codes related to concrete materials like aggregates/admixtures/cement or mix design in general as it is one of the subjects i am constantly involved in. I do mix design analysis and reporting , Project conformance analysis, mix optimisation using Shilstone/TPM/CPM. In this particular subject I also depend on ASTM codes and other publications/books heavily.

I use ACI design codes from time to time and specifically those related to calculations and I use these calculations in my planning process as well. An example is 347.2R05 and 347 which I recently used to make PT slabs construction cycle calculations using design and construction loads as well as calculations for formwork striking purposes like punching shear, deflection moments although this is not specifically ACI 347.2R05

I also constantly use all codes related to field practice and inspections as I am constantly present on sites as well.

So to name a few 117-06, 201.2, 209.2, 211.1, 212.3, 212.4, 221, 224, 228.1, 232.2, 301, 302.1, 303, 303.1, 304, 304.2, 305, 306, 308, 309, 309.1, 309.2, 318, 332, 347, 347.2,....

What about you?

Dear Roland,

Thank you for your kind reply. It is most appreciated. My work is related to Construction as well, but on the management side. I was on the Client representative; CM/Engineer for the past 4 years. Now I am engaged at the preconstruction stage with Value Engineering, and during the Construction Stage, I provide Project Management, Planning and Scheduling, Contract Management, Dispute Resolutions, and Cost Reduction Consulting Services.

Since the subject is planning and scheduling, I was interested in knowing what the ACI mentioned about the subject matter. Hence the question.

With kind regards,

Samer

Hello Samer,

ACI doesn’t really discuss the planning and scheduling processes. Its more about technical engineering stuff as you already know.

I guess for those scheduling issues, we’ll have to look somewhere else. Unfortunately , even up to this date those organisations concerned with the planning function still do not agree on everything. But maybe thats the beauty of it.

The only ACI I have used in an indirect manner in my planning function is ACI 347.2 by calculating constructoin cycle times especially when the contractor had slab formwork shortage or constraints.

To get back to the subject of this post, I Would have liked that the post initiator answers the new questions so that we get to an agreement on the duration.
But I still have a doubt that one tower crane is enough.
Regards
Roland

Dear Roland,

You are correct, one crane will be fully engaged around the clock. But if he install it at the middle with a 50 Boom, it will cover the 92m direction. The laydown area has to be along the longer edge. This is site dependent.

Actually, he does not need any Tower Crane until he gets high up over the 3rd or 4th Floor. But that will increase the handling time, and increase cost.

With kind regards,

Samer

I guess the necessity of a Tower Crane depends on many factors, some of which are :
1- Not all contractors use lightweight modular formwork or site erected formwork. Some systems are based on heavy steel based studs. We use such systems actually. Of course the alternative would be a telescopic mobile crane but the costs are then higher.
2-The necessity of the tower crane is also related to whether the ready mix concrete provider is able to provide a pump for each and every pour independent of the quantity to be poured. If not then a crane might then be necessary on a frequent basis.

I can really think of many reasons for which tower cranes are necessary especially for middle-size and large projects.

Furthermore, the 2 factors mentioned above influence the capacity of the tower crane as well.
For example: if the contractor uses lightweight modular formwork then tower crane has more time to assist other tasks and so on.

So yes it depends. If all those factors are taken into consideration , the usage of one crane might be sufficient. If not , 2 are better then one. Usually a combination of a large crane with a 50m boom and a smaller one with a 32m to 36m boom is one of the best options.

Regards,
Roland

Hey Guys

Why dont we all get together and do the programme for Mukunda.

Only if it is done bottom up and on Powerproject - I could do it in about 90 minutes - finishings and MEP together.

Best regards

Mike Testro.

Dear Roland,

Of course a Contractor working on such a project would need modular Formwork. It will prove to be faster and cheaper. For the lower floors, this can be served from the side with mobile cranes. Once you go higher, it becomes more difficult.

At the start of the project, you might have the mobilization complete. Mobile cranes can serve until the Tower crane is installed.

You are correct, we need more info from Mukunda to provide him with the best answers.

With kind regards,

Samer

Hi Mike,

I think that you are right. Lets do it in 90 minutes next time Mukunda is online. It will be a nice excersise. All Milestones, Activities, Resources and Durations. He can cut and paste it into his own software.

With kind regards,

Samer

Hi Samer

I am not doing much on Saturday morning - I’ll have it ready by 12:00 noon.

When can we expect yours?

If Mukanda wants it on P3 or MSP I can convert it but it will not be so flexible.

Best regards

Mike Testro.

Dear Mike,

Ready anytime Mukunda is online :).

I prefer all the information is presented here so others can make use of it.

With kind regards,

Samer

Hi All

The detailed programme is ready for distribution.

It took 235 minutes - not the estimated 90.

Send me an email to planning.services@xlninternet.co.uk and I will attach a copy in PowerProject v10.

Meanwhile you can download a freeviwer from the Astadev.com website.

Best regards

Mike Testro.

I remember one project stretching around 300m X 50m and around 15m deep, two tower cranes were beautifully shown on drawings with accurately calculated stretches, but these tower cranes were supposed to be temporarily installed in the raft foundation.

Well, I guess they end-up handling the rebars for the raft foundation manually (a couple of hundred tons)...

Hey Anoon,

What you just described is exactly how most people do things round here especially what concerns Raft Foundations without tower cranes

Regards,
Roland

What happened to the Asta website? I can’t access it since yesterday afternoon ... grrr

Dear Planners
Thanks for the suggestions....

Mike if u pass me through MSP will be good for me
my mail id: please contact Mukunda through the private message service.
Many Thanks

Hi Roland

I got through just now.

Best regards

Mike Testro

Yes well .

For some reason it is the only website not opening.
It stalls on "Connecting" forever.

what browser are you using? I am on IE.

regards
Roland

Hi Roland

Copy & Paste:

www.astadev.com

It just worked again - good luck

Best regards

Mike Testro

I cant believe you just said that. -_-
It seems that my laptop doesn’t like Asta while my desktop has no problem .
go figure.
Regards
Roland

Just downloaded Asta Project Viewer.
Very nice work Mike. Thank you for sharing :)
regards

Roland