MS Tower is a specialized program for the structural analysis, checking, design and management of steel towers, masts and poles used in the communications, tele com, broadcasting and power transmission industries. The program is flexible and is organized so that it can be integrated into a bus iness's management system while being the backbone of the Structural Engineers d epartment. Features in the program enable the management side of the program to be web enab led so that aerials on structures and their properties may be examined on the we b while structural and contract information is retained on the companies private network. MS Tower contains options for defining the geometry, loading, analysis, graphica l viewing of input, verifying input, graphical viewing of results, and member ch ecking. Codes of PracticesThe set of codes for the design and checking to the European C odes 1 and 3 have not yet been completed with the the British National Annex sti ll pending. When published we will be able to progress to completing our work to these stand ards and verification of calculations. Loading may be computed in accordance with: BS 8100:Part 1, 1986, (Amd 1, 2005) BS 8100:Part 4, 1995, (Amd 1, 2003) BS 6399:Part 2, 1997 CP3 Chapter 5 ILE TR7, 2000 EIA/TIA-222-G, 2005/7 + Addendum 2 EIA/TIA-222-F, 1996 ASCE 7-02 AS 3995, 1994 Malaysian Electricity Supply Regulations, 1990 IS:875 (Indian Standard) BNBC (Bangladesh National Building Code) Earth Quake (Response spectrum Analysis) Earth Quake (Lateral Acceleration) Earth Quake (Equivalent lateral force method of EIA 222-G) Member and bolt capacities may be checked against the requirements of: BS 8100:Part 3, 1999, (Cor' 1, 2001) EIA/TIA-222-G, 2005/7 + Addendum 2 EIA/TIA-222-F ,1996 ASCE 10-97 ASCE 10-90 ASCE Manual, 72 BS 5649 part 7 ILE TR7, 2000 BS5950 (Poles only) BS 449 (No bolt checking) AS 3995, 1994 IS:802 (Indian Standard) Towers, which may be of three, four or multi sided, are assembled by combining a series of standard face, plan, hip and cross-arm panels. The tower profile is d efined by giving the height of individual panels and the width at "bend" points. All other widths are obtained by interpolation. The range of standard panels is being regularly increased with over 200 different panel types available at pres ent. Standard panels are parameterised so that the user may readily modify the c onfiguration.
If a suitable standard panel is not available the system accepts "user-defined p anels" (UDP's). While these require more data than a standard panel, they allow the system to be used for virtually any tower configuration. A UDP may consist of anything from a few members that make up half a face panel to a full three-dimensional section of the tower. The result of the tower building process is a complete MS Tower data file, Job.M ST, where "Job" is the MS Tower job name. The loading module of MS Tower computes loads due to self-weight, ice, and wind on the tower. As well as computing wind loads on the bare tower the program is a ble to take account of a wide range of ancillary items found on communication to wers. Ancillaries are classified into the following categories: Large ancillaries, mounted out from the face of the tower and consisting of larg e dishes whose wind resistance is significant compared with that of the structur al members of the tower. Linear ancillaries, normally within the body of the tower and consisting of item s such as ladders, feeders and wave-guides. Face ancillaries, attached to the face of the tower and consisting of small item s such as minor antennae, gusset plates and platforms. Insulators, located between the segments of multi-segment guys. Resistances, either additive or total, may be used to model the loading on secti ons of the tower. For example if a section of a tower is completely clad in pane ls, it may be more accurate to use an overall resistance for this section that t o use a sum of the loads on individual panels and section of the tower. Ancillary libraries containing data describing the physical and drag characteris tics of a wide range of antennae types are provided withMS Tower. The libraries are plain text files and may be easily added to by users. For a dish antenna the library would typically include its diameter, mass, location of centre of gravi ty, surface area that may be coated with ice, and its projected area and drag co efficients for a range of angles of incidence. Six aerodynamic coefficients are specified for each angle of incidence to enable antenna forces and moments to be computed automatically. The use of ancillary libraries simplifies the preparation of the data needed to compute the loads on the tower. To fully describe an antenna its library referen ce, its location on the tower, and its bearing are required. MS Tower will extra ct all other data from the library, compute the forces acting on the antenna (de ad load, ice-load, and wind loads) and transfer them into the tower as a set of statically equivalent forces. To assist in checking of input data MS Tower displays the tower and all linear a nd large ancillaries. As well as the visual display, any ancillary may be querie d by "picking" with the graphics cursor to obtain its identification, location, library reference, and other pertinent data. Wind forces may be computed using either mean, fastest mile or gust wind velocit y. In the former case, the member forces for wind load cases are increased after analysis using gust factors computed in accordance with BS 8100 or EIA-222. For masts, patch wind loading cases may be computed and combined in accordance with BS 8100:Part 4. Any wind profile can be specified. The strength of members may be checked against the rules of the codes listed abo ve, with the results available as a summary report giving the critical load case
and condition or a larger detailed report suitable for checking the computation s for each member. The results of the member check may be shown as a graphical d isplay with the colour in which a member is displayed depending on its maximum l oad/capacity ratio. Foundation reactions and ancillary rotations may also be reported for any probab ility.
