Deflections during Construction Staging Analysis

Creation date: 6/25/2020 2:59 AM Updated: 6/25/2020 12:45 PM construction camber construction stage analysis control current step displ initial tangent displacement stage/step real displ understanding deformation behavior

Question:

Can you please provide confirmation as to how Midas treats deflections of multiple segments during a construction staging analysis? I have this option on in my model

Answer:

Hi, Thanks for writing to us.

Understanding deformation behavior in Construction Stage Analysis:

Example problem: Consider a cantilever that will be cast in three parts.

To simulate the above construction stages in Midas, we have created three stages as shown below CS1, CS2, CS3 (green dashed line indicates the construction joint).

Deformation results in each CS stage after analysis are as below:

In Midas Civil, we have three deformation results

1) Construction stage deformation (CS deformation)

2) Current Step Displ.

3) Stage/Step Real Displ.

Let us dissect how Midas calculates the deformation results in each CS stage:

CS1 --> CS1 deformation = (current step Displ. of CS1)

CS2 --> CS2 deformation = (CS1 deformation) + (current step Displ. of CS2)
CS3 --> CS3 deformation = (CS2 deformation) + (current step Displ. of CS3)

CS1 --> CS1 Stage/Step Real Displ. = (current step Displ. of CS1) + (Tangent displacements)

CS2 --> CS2 Stage/Step Real Displ. = (CS1 deformation) + (current step Displ. of CS2) + (Tangent displacements)
CS3 --> CS3 Stage/Step Real Displ. = (CS2 deformation) + (current step Displ. of CS3) + (Tangent displacements)

Based on the above formulas, we can validate the CS2 deformation = (CS1 deformation) + (current step Displ. of CS2); by preparing another model which has the below load pattern and then running a simple static analysis.

Adding above to displacements gives us the below displacements. CS2 stage deformation = [(CS1 deformation) + (current step Displ. of CS2)]

where as Stage/Step Real Displ. values are below (where tangent displacements are additionally added).

PFA the verification models.

Thanks,

MIDAS TECH SUPPORT

DataImage21.png

DataImage58.png

1_Cantilever_With TangDisp - JackSupport - Original.mcb

DataImage5.png

Initial Tangent Displacement Verification.rar

DataImage94.png

Def_Camber_1_With TangDisp_CS2- Static Only.mcb

Def_Camber_1_With TangDisp.mcb

DataImage47.png

Files		Sort by Name Sort by Date
	DataImage21.png 131 KB
	DataImage58.png 210 KB
	1_Cantilever_With TangDisp - JackSupport - Original.mcb 59 KB
	DataImage5.png 114 KB
	Initial Tangent Displacement Verification.rar 546 KB
	DataImage94.png 139 KB
	Def_Camber_1_With TangDisp_CS2- Static Only.mcb 55 KB
	Def_Camber_1_With TangDisp.mcb 54 KB
	DataImage47.png 66 KB

Deflections during Construction Staging Analysis

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