Problem in restrainer cable modeling in OpenSees

[ehsanomranimemphis]

I modeled a two spans bridge (simply supported) in OpenSees. I am going to add a restrainer cable element to connect deck to column. Restrainer cables are only tension elements. So I used uniaxialMaterial ElasticPPGap material and I used truss element to assign this material to it. I wrote the following commends:

set Ecable [expr 10007.6*144];
set Fycable [expr 175.5*144];
set gap 0.064;
set eta 9.5
set matTag 390
uniaxialMaterial ElasticPPGap $matTag $Ecable $Fycable $gap $eta
element truss 500 38 89 10.00154 $matTag
element truss 501 40 89 10.00154 $matTag

(units: Lb-ft)
But the problem is that there is not any difference between response of bridge with and without adding cables. I checked the longitudinal displacement and rotation in the center node of deck in both models (model without restrainer cable and the model with restrainer cable).
Is there anyone to help me?

[ehsanomranimemphis]

Is there someone to be able to help me?

[selimgunay]

If the truss deformations are not exceeding the specified gap amount, there won't be any stiffness and retoring force provided by the truss and yo will get the same responses for the cases with and without the truss. This could be the reason