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Formwork Rent Simulation

10 replies [Last post]
Bogdan Leonte
User offline. Last seen 3 weeks 21 hours ago. Offline
Joined: 18 Aug 2012
Posts: 240

Hello,

I am trying to model the following scenario, but with little luck. Maybe Rafael or Vladimir cand help me a bit.

Scenario:

01. Formwork for columns is rented, 1 set (column) = 1000 currency/30 days, 1 set = 25 currency/day.

02. Formwork for columns rent is a minimum of 30 days. After 30 days the rent becomes 25 currency/day. If the formwork is rented less than 30 days the rent is still 1000 currency.

03. Formwork should be delivered on site 1 day earlier than the first activity of Column formwork instalation.

04. Number of crews for cast in place columns is another variable for this scenario.

Purpose: I would like to run different scenarios to see which is the best reasonable solution depending on the number of crews and number of sets of Column formwork the company rents. Is it more advantageous to use 2 crews and 10 sets or 1 crew and 20 sets of column formwork.

Here is how I started:

01. 3 Phases of columns, each phase has 10 columns

02. 1 Phase for formwork delivery, return. Formwork delivery milestone, formwork return milestone. 30 days rent limit milestone, daily rate over 30 days hammock with 1 minute calendar and hourly cost.

03. Column curing and Column formwork removal have strict link.

04. Formwork delivery has all Column reinforcement FF(-1d). This is not correct but if I make all Column reinforcement activities as successors of the Formwork delivery with lag +1 day and set Formwork delivery to ALAP this will not work because Formwork delivery will not be schedules ALAP due to the fact that the 30 days rent limit activitity is scheduled ASAP.

05. There is a problem with the model in the scense that Formwork delivery takes place on the 17.03 but one Column formwork instalation activity start on the 16.03. This can be fixed by setting profiles.

06. I setup Formwork material consumption and revenue for Formwork Delivery, Formwork Return, Column formwork instalation and Column formwork removal.

Here are pictures, and the file:

8096
screenshot_2022-02-26_230100.png

https://postimg.cc/MMnKHQ8K

https://www.mediafire.com/file/g66vp9hiuk0a7fj/Cofraje_Metalice.001.sprj...

Any advice is very appreciated.

Best regards,

Bogdan

Replies

Bogdan Leonte
User offline. Last seen 3 weeks 21 hours ago. Offline
Joined: 18 Aug 2012
Posts: 240

Thank you for your contribution Marcus!

I looked over your model and I have the following observation: Activity „deliver on site 1 day earlier” should be for all sets, at once, nor for each Phase. As you modeled it this activity delays 1 day for each Phase, on a 5 storei building and 3-4 phases per level this willl mean 15-20 days delay.

In the pictures you have an hourly cost (Daily rate over 30 days), and from the form and date of the hammock, I susspect it is a 8 hour/day. You must take into consideration that the cost is per day...if activities have less than a round day the over 30 days cost will be distorted, not by much but it will.

The file you have attached is Rafael's original model, not the one in the pictures. 

Best regards,

Bogdan

Marcus Possi
User offline. Last seen 20 hours 58 min ago. Offline
Joined: 27 Feb 2010
Posts: 62

Hi Bogdan

I made some studies ...

Using profiles property in "material allocation" - using two diff hammocks to support your considerations, and using an extra activity to support the "arriving of framework kit",  I think it is another point to consider in our debate.pic 1 - here 

 

pic 2 - here 

file here

Rafael Davila
User offline. Last seen 10 hours 45 min ago. Offline
Joined: 1 Mar 2004
Posts: 5169

Good, no doubt a word to the wise is enough.

Bogdan Leonte
User offline. Last seen 3 weeks 21 hours ago. Offline
Joined: 18 Aug 2012
Posts: 240

Hello Rafael,

Thank you for the samples, they are quite elegant.

Best regards,

Bogdan

Rafael Davila
User offline. Last seen 10 hours 45 min ago. Offline
Joined: 1 Mar 2004
Posts: 5169

Spatial resources are required by a group of activities, rather than a single activity as renewable resources. The spatial resource is occupied from the first moment an activity from the group starts until the finish of all activities from that group. 

In the case of elevated slab forms you have no option than to keep them within the building before moving to another building.

In this case we used a spatial resource to keep a column set occupied within a group of activities. If we also want to keep a crew occupied within a group of activities before allowing it to move to another group we must create an additional spatial resource and keep the spatial resources nested, please take a look at the following schedule versions.

https://www.mediafire.com/file/dwfmw6pyti5x9c4/Cofraje_Metalice_Rafael.002.sprj/file

https://www.mediafire.com/file/mlprpdckdw5xf6k/Cofraje_Metalice_Rafael.003.sprj/file

Bogdan Leonte
User offline. Last seen 3 weeks 21 hours ago. Offline
Joined: 18 Aug 2012
Posts: 240

Thank you for the PDF presentation.

I noticed the Create column formworks milestone and it's negative material consumption.

Rafael Davila
User offline. Last seen 10 hours 45 min ago. Offline
Joined: 1 Mar 2004
Posts: 5169

These days not all labour is „skilled”  - this is common in many jobs.

Spatial-Resource to change form sets just change material consumption here.

For a PDF of my presentation click the following link and download.

https://www.mediafire.com/file/t6raioys2v4mlks/Spatial_Resources.pdf/file

Bogdan Leonte
User offline. Last seen 3 weeks 21 hours ago. Offline
Joined: 18 Aug 2012
Posts: 240

Vladimir,

It probably is an isolated incident, I could not reproduce it in any other scenario.

Thank you for the reply.

 

Rafael,

thank you for the assitance, the model is great. I made some adjustments to your proposal and still works very well.

These days not all labour is „skilled” (at least with what I deal with), usually there is 1-2 skilled rebar mounter, 1-2 skilled carpenter and the rest are unskilled workers. A team of 6 people (for example) they do all the works associated with cast in place concrete works. This is the reason my model had only 1 resource.

The adjustments are as follows: assigned curing 24h/7d calendar and made the link between pouring concrete and curing strict (and surprisingly it is respected for all 4 phases) in order to make the model more realistic, finally I assigned only 1 resource - Concret Workers (as it is with what I have).

Once againg thank you for the help!

Best regards,

Bogdan

Hi Bogdan,

thank for your example.

We will look tomorrow why in Spider Project schedule formwork installation starts two minites earlier than formwork delivery.

Best Regards,

Vladimir

Rafael Davila
User offline. Last seen 10 hours 45 min ago. Offline
Joined: 1 Mar 2004
Posts: 5169

Explore the following model, it is setup for 2 form sets and crews are different.

https://www.mediafire.com/file/2wsb1bot6fo6wud/Cofraje_Metalice_Rafael.001.sprj/file