To compare the ability of the portal frame to resists vertical and horizontal loadings. The Plastic Bending of Portals experiment consists of a specimen steel portal frame held firmly at the bottom corners by two fixing blocks ensuring an encastre fixing. Two load cells load the specimen frame by wires and adjustable pulleys. These ensure the loads pull the frame in the correct direction.
To establish the relationship between applied load and horizontal reaction at the pinned support.
To observe the effect of the load position on the horizontal reaction. The connections between the columns and the rafters are designed to be moment resistant, i.
Because of these very strong and rigid joints some of the bending moment in the rafters is transferred to the columns.
This means that the size of the rafters can be reduced or the span can be increased for the same size rafters. This makes portal frames a very efficient construction to use for wide span buildings.
Portal frame construction is therefore typically seen in warehouses, barns and other places where large, open spaces are required at low cost and a pitched roof is acceptable. Generally portal frames are used for single storey buildings but they can be used for low rise buildings with several floors where they can be economic if the floors do not span right across the building in these circumstances a skeleton frame, with internal columns, would be a more economic choice.
A typical configuration might be where there is office space built against one wall of a warehouse. Portal frames can be clad with all sorts of material but the most popular solution, for reasons of economy and speed, is some form of lightweight insulated metal cladding with cavity masonry work to the bottom 2m of the wall to provide security and impact resistance.
The lightweight cladding would be carried on sheeting rails spanning between the columns of the portal frames. The load cell is connected to the digital indicator. The indicator is switched on.
The indicator must be switched on for 10 minutes before taking readings for stability of the reading.
A load hanger is placed at the location where the load is to be applied. The indicator reading is noted. The tare button is pressed if it is not zero.
A load is placed on the load hanger. The indicator reading is recorded. This represents the horizontal reaction of the pinned support. The load is increased on the load hanger and the horizontal reaction is recorded.
Step 7 is repeated for another four load increments. The result of the experiment is tabulated. The equations for the horizontal reaction at the pinned support A of a portal frame are given below: The best straight line is drawn through the points plotted.
From the graph plotted, the slope of the line, m is determined. Therefore, the percentage error of this experiment is: There is a variation between experimental and theoretical data, 4.Portal frame construction is a method of building and designing simple structures, primarily using steel or steel-reinforced precast concrete although they can also be .
INTRODUCTION Frame is a structure elements composed of beams and column connected by rigid joints. The angle between the beam and column is usually Figure 1 shows a simple frame which consists of a column and girder/5(2).
Experiment Portal Frame (Plastic Bending of Portals) AIM: To compare the ability of the portal frame to resists vertical and horizontal loadings. Portal frame construction is a method of building and designing simple structures, primarily using steel or steel-reinforced precast concrete although they can also be /5(10).
Report Portal Frame. Topics: Pulley, The portal frame is an indeterminate structure to several degree of indeterminacy depending on the end conditions To know the behavior of any frame it is advisable to know its different deflected shapes under different . The most common form of portal frame used in the construction industry is the pinned-base frame with different rafter and column member size and with haunches at both the eaves and apex connections (Fig.1).
These two important design features of the modern.