28/03/2022

Beam Design Optimization

MiLA Structure’s beam rebar selection algorithm consists of three different types of optimization methods, in which the user may select. The main objective of this beam design optimization is to suit the user’s preference on how they wish to prioritize the rebar arrangement, which would result in cost savings or project’s simplicity purposes. 

The summary table below shows the types of rebar optimization methods with its process’ description.

Optimization MethodDescription
Single Layer Reinforcement PriorityRebars will be arranged at the bottom-most level only. Consist of only one layer of reinforcement.
Smaller Bar SizeThe smallest rebar size selected by the user will be used first at full capacity before stepping up to the next rebar size.
Lesser Number of BarsThe number of rebars are kept at minimal while the rebar size continues to increase.

OPT 01: NONE (SINGLE LAYER REINFORCEMENT PRIORITY)

Single layer reinforcement – Rebars are to be arranged at bottom level only. (One layer)

For single layer reinforcement priority, the steps are as follows:

1.    The steel area required (As req) is determined.

2.     The Minimum and Maximum Spacing (rebar-to-rebar) is determined. This parameter is set in the Project Settings.

3.     Program will run by first using the rebar of the smallest diameter selected by the user from the Project Settings. A minimum of two(2) rebars is first assumed, then gradually increasing the number of rebars (As supplied), until the As required is achieved.

4.     The maximum limit number of rebars will be obtained when the rebar spacing is no longer larger than the minimum rebar spacing. The As supplied will be compared to the As required. If still smaller, the program will select the next rebar size, and the process will be repeated until the As supplied is more than the As required. Note that under the Single Layer Reinforcement Priority method, there will be no 2nd layer or 3rd layer reinforcement added. 

OPT 02: SMALLER BAR SIZE

Smaller bar size – The smallest rebar size selected by the user is first utilized before increasing rebar size.

For smaller bar size method, the steps are as follows:

1.     The steel area required (As req) is determined.

2.     The Minimum and Maximum spacing (rebar-to-rebar) is determined.

3.     Program will run by first using the rebar of the smallest diameter selected by the user from the Project Settings. A minimum of two(2) rebars is first assumed, then gradually increasing the number of rebars (As supplied), until the As required is achieved.

4.     Upon achieving the As required, the rebar-to-rebar spacing checks are done. If the spacing is too less, the program will select the next rebar size and the process will be repeated until the As supplied is more than the As required. Whereas, if the spacing is more than the maximum spacing, rebar of the same size will be added until the spacing falls between the minimum and maximum range. 

OPT 03: LESSER NUMBER OF BARS

Lesser number of bars – Number of rebars kept at minimal while size of rebar continues to increase.

For lesser bar size method, the steps are as follows:

1.     The steel area required (As req) is determined.

2.     The Minimum and Maximum spacing (rebar-to-rebar) is determined.

3.     Program will run by first using the rebar of the smallest diameter selected by the user from the Project Settings. Two(2) rebars are first assumed, then gradually increasing the size of rebars (As supplied), until the As required is achieved.

4.     If maximum rebar size chosen by user still exceeds maximum spacing, another rebar will be added until spacing falls between minimum and maximum range.

-Brahmayudan, Technical Civil Engineer-