The next step is to define the load effects for construction stage 1. This may be necessary to ensure that all the different load case shears are of the same type.Ĭlose the Define Pre-Tensioned Beam Loads form with the ✓ OK button. Note that by default the calculated shears are Absolute Shear values but can be changed to Real Shear using the radio button at the bottom of the Define Pre-Tensioned Beam Loads form. The Define Pre-tensioned Beam Loads form will now show the total load applied by the four load components. In the Increments section, set Beam span equally divided by to “50” then click ✓ OK to close the Generate Beam Loads form. Leave all the other fields at their default values and set the Component Ref. to “Right Temp Support."įinally, the temporary load due to construction and water in the wet concrete needs to be defined.Ĭlick on the Add Load Component button again and enter the UDL Intensity Start and End as “1.4kN/m”. to “Left Temp Support."Ĭlick the Add Load Component button and repeat the process (remembering to make ULS and SLS Load Factors negative), this time setting the Start Dimension to “19.95m”, the End Dimension to “20.05m” and the Component Ref. Set Start Dimension to “0.95m” and the End Dimension to “1.05m".Ĭhange the ULS and SLS Load Factors to “-1.35” and “-1” respectively to make this an upward load and set the Component Ref. The equivalent applied UDL intensity over a 100mm length is 1410.213kN/m.Ĭlick the Add Load Component button and enter the UDL Intensity Start and End as “1410.213kN/m”. Since the program can’t apply a point load to a beam, this needs to be applied using two, 100mm long UDLs. The UDL intensity is 13.4306kN/m which applies a total load of 282.0426kN to the beam. This load needs to be applied equally to the two temporary support locations. The program automatically calculates the dead load for the beam and adds it as the first component of the generated load, called “Beam dead load”. The Generate Beam Loads form will now open. To add a this erection load effects open the Define Pre-Tensioned Beam Loads form using the button, in the toolbar of the navigation window, and select Beam Loads | Beam Erection.Ĭlick the Generate button and then click on “Yes” on the confirmation form that appears. Next we will define erection of beam loads using the “Generate” facility to include two extra components one for the temp 1kN/m and the other for the support loads (upwards). to set the title as “Prestressed Concrete Beam” with a sub-title of “Example 5.2”.Īlso change the Job Number: to “5.2” and add your initials to the Calculated by data item if necessary.Ĭlick ✓ OK to close the titles form. Start the program and open the data file “EU Example 4_3.sam” created in section 4. For longitudinal shear it can be assumed that the interface surface is Type 2. The reinforcement grade for the shear links is the same as that for the main reinforcement and the vertical shear is resisted by the precast beam only. Shear link spacing in the beam also needs to be determined to resist both transverse and longitudinal shear forces. It is required to design the required tendon layout with appropriate debonding so that SLS and ULS design criteria for bending moments and stresses are met during transfer, beam erection and during normal use. The differential shrinkage strain should be -0.0001 and the creep coefficient set to 1.5. The shrinkage strain for the concrete is to be set to -0.00025 with 20% of this occurring before the insitu slab is cast. The temperature profile to be applied to the section is in accordance with Differential Temp Fig 6.2, with a surfacing finish 100mm thick. There are no secondary effects due to differential temperature and shrinkage, as the beam is statically determinate, but the primary stresses need to be included for both, where appropriate. Max live load bending (with associated shears) and shear effects (with associated moments) have been prepared in an external ASCII file as envelopes. This load and the temporary supports are removed once the concrete has hardened. There is also a temporary load of 1.4kN/m over the length of the beam which represents temporary construction loads and the water in wet concrete. During construction the beam is initially supported on temporary supports at 1m from the beam ends.
![sam the ultimate mechanism designer sam the ultimate mechanism designer](https://i.ytimg.com/vi/dtKrrf8YMDY/maxresdefault.jpg)
The bending and shear effects due to dead load and superimposed dead load (2.5kN/m) are created by using the “Generate” feature in the program. The dimensions of the beam can be found in example 4.3.
![sam the ultimate mechanism designer sam the ultimate mechanism designer](https://m.media-amazon.com/images/I/61SpZqVmIkL._AC_SL1500_.jpg)
The beam is an internal beam of a simply supported bridge deck of 21m span and the 2m wide concrete slab is cast in one. A composite pre-tensioned pre-cast beam and concrete slab is shown below.