Setting of Displacement Upper Limit for Specific Boundary in Linear Elastic Analysis

Dear FF++ developpers and users.

I am interested in setting upper displacement limits for certain boundaries for linear elastic bodies.
Does anyone know how to do this?
I considered adopting the penalty method, but it did not work.

+int1d(Sh,Gamma)(1e10*(u1-u1Max)*tu1)

for example, where u=[u1, u2], tu=[tu1, tu2], real u1Max=10.0

Sincereley
Ayataka