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Critical normal traffic loading for flexure of bridges according to TMH7Malan, Andreas Dawid 03 1900 (has links)
Thesis (MScEng)--Stellenbosch University, 2013. / ENGLISH ABSTRACT: Different types of live loading due to traffic may act on bridges. The focus of this study is on
normal traffic loading according to the South African specification of TMH7. Heavy vehicles are not
included in normal traffic loading. TMH7 represents the code of practice for the design of highway
bridges and culverts in South Africa. The aim of the study is to provide an insight into the
flexural
analysis of skew bridges, under the effects of normal traffic loading.
The need for the study arose since the specification of TMH7 does not explicitly specify application
patterns for normal traffic loading. Only the intensity of normal traffic loading is specified and it
should be applied to yield the most adverse effects. For these reasons, a set of so-called standard
application patterns are investigated and developed through the course of this study. The envelope
of the values from the standard application patterns are compared to the most adverse application
pattern for
flexural effects in certain design regions of the bridge deck. Flexure, as in the context of
this study, translates into the bending and twisting of the bridge deck under loads.
A number of numerical experiments are performed for typical single span and multi-span
continuous carriageways, where the standard application patterns are compared to the most adverse
application patterns. The results from the numerical experiments are documented and compared as
the angle of skew of the bridge deck increases in plan-view. For this purpose, the development of
effective and specialized software was necessary.
It was found that the set of standard application patterns can be used as a preliminary approximation
for the most adverse effects of normal traffic loading, for specific
flexural resultants in certain
design regions of a bridge deck. However, for a large number of secondary
flexural effects, the set of
standard application patterns did not represent a good approximation for the most adverse values. / AFRIKAANSE OPSOMMING: Verskillende tipes lewendige belasting, as gevolg van verkeer, kan op brûe inwerk. Die fokus van
die studie is op normale verkeers-belasting volgens die Suid-Afrikaanse spesifikasie van TMH7.
Swaar-voertuie word nie ingesluit by normale verkeers-belasting nie. TMH7 verteenwoordig die kode
vir die ontwerp van padbrûe en duikers in Suid-Afrika. Die doel van die studie is om insig te verskaf
in die buig-analise van skewe brûe, as gevolg van die werking van normale verkeers-belasting.
Die rede vir hierdie studie ontstaan aangesien die spesifikasie van TMH7 nie eksplisiet aanwendingspatrone
vir normale verkeers-belasting voorskryf nie. Slegs die intensiteit van normale verkeersbelasting
word voorgeskryf en dit moet aangewend word om die negatiefste effekte te verkry. Vir
hierdie redes word 'n versameling van sogenaamde standaard aanwendings-patrone deur die loop van
die studie ondersoek en ontwikkel. Die omhullings-kurwe van die waardes wat deur die standaard
patrone gelewer word, word vergelyk met die waarde van die aanwendings-patroon wat die negatiefste
buig-effek in sekere ontwerp-areas van die brugdek veroorsaak. Buig-effekte, soos van toepassing op
hierdie studie, verwys na buig en wring van die brugdek as gevolg van belastings.
'n Aantal numeriese eksperimente, vir enkel-span sowel as multi-span deurlopende brugdekke,
word uitgevoer en die standaard aanwendings-patrone word vergelyk met die aanwendings-patrone
wat die negatiefste waardes lewer. Die resultate van die numeriese eksperimente word gedokumenteer
en vergelyk soos die hoek van skeefheid van die brugdek in plan-aansig toeneem. Vir hierdie doel is
die ontwikkeling van effektiewe en gespesialiseerde sagteware dus nodig.
Daar is gevind dat die standaard aanwendings-patrone, vir spesifieke buig-resultante in sekere
ontwerp-areas van die brugdek, as 'n voorlopige benadering vir die negatiefste effekte van normale
verkeers-belasting gebruik kan word. Dit was egter verder gevind dat vir 'n groot aantal sekondêre
buig-effkte, die versameling standaard aanwendings-patrone nie as 'n goeie benadering vir die
negatiefste waardes dien nie.
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