Relative Vertical Movements Research Articles

New Geomorphological and Historical Elements on Morpho-Evolutive Trends and Relative Sea-Level Changes of Naples Coast in the Last 6000 Years

This research aims to present new data regarding the relative sea-level variations and related morpho-evolutive trends of Naples coast since the mid-Holocene, by interpreting several geomorphological and historical elements. The geomorphological analysis, which was applied to the emerged and submerged sector between Chiaia plain and Pizzofalcone promontory, took into account a dataset that is mainly composed of: measurements from direct surveys; bibliographic data from geological studies; historical sources; ancient pictures and maps; high-resolution digital terrain model (DTM) from Lidar; and, geo-acoustic and optical data from marine surveys off Castel dell’ Ovo carried out by using an USV (Unmanned Surface Vehicle). The GIS analysis of those data combined with iconographic researches allowed for reconstructing the high-resolution geomorphological map and three new palaeoenvironmental scenarios of the study area during the Holocene, deriving from the evaluation of the relative sea-level changes and vertical ground movements of volcano-tectonic origin affecting the coastal sector in the same period. In particular, three different relative sea-level stands were identified, dated around 6.5, 4.5, and 2.0 ky BP, respectively at +7, −5, and −3 m MSL, due to the precise mapping of several paleo-shore platforms that were ordered based on the altimetry and dated thanks to archaeological and geological interpretations.

Briefing: Case studies for movement gauges to record vertical movements in structures to ±0·1 mm

Extraordinary controversy continues to exist within the engineering profession over monitoring of movements and even over the underlying reason why useful and repeatable data are needed. Previous papers on this subject have shown that cracks only indicate the symptom of movement, but cannot reliably demonstrate the cause or even the form of movement. Monitoring of just the cracks often results in inadequate or inappropriate remedial works. Movement gauges can quickly and cheaply provide readings of relative vertical movements to 0·1 mm. Case studies illustrate advantages over the Building Research Establishment’s precise levelling approach; how understanding of the characteristics of the ground movement helped forensic investigations of both a castle keep and a 1960s tower block; and how needless underpinning of a domestic property was avoided using vertical monitoring.

ДВИНСКИЙ ЗАЛИВ БЕЛОГО МОРЯ В ПОЗДНЕЛЕДНИКОВЬЕ?- РАННЕМ ГОЛОЦЕНЕ, "Геоморфология"

На основе новых оригинальных данных о строении рельефа и отложений побережья Зимнего берега Белого моря от м. Керецкий до р. Куя, полученных методами геоморфологического профилирования, литостратиграфических описаний, радиоуглеродного датирования и диатомового анализа, а также анализа опубликованных геолого-геоморфологических материалов, восстановлены детали истории развития рельефа дна и побережья Двинского залива в поздне- ледниковье и раннем голоцене. Дана оценка хода изменений относительного уровня моря и скорости относительных вертикальных движений побережья. Установлено, что на северо-восточном берегу Двинского залива террасы высотой 5-20 м сформировались в ходе позднеледниковой трансгрессии - ранее, чем 9030±80-8410±40 14С (~10.2-9.4 тыс.) кал.л.н. Амплитуда трансгрессии, по ориентировочным оценкам, не превышала 15-16 м относительно современного уровня моря. Северо-восточное побережье залива (Зимний берег) испытывало относительное поднятие со скоростью около 0.2-0.5 мм/год, меньшее, чем Летний берег, что не может быть объяснено исключительно гляциоизостазией. Дельта р. Северной Двины была относительно стабильна. В конце пребореала - начале бореала на берегах залива фиксируется регрессия, протекавшая на фоне резкого увеличения притока в акваторию баренцевоморских вод.

Submerged and buried Pleistocene river channels in the Gulf of Trieste (Northern Adriatic Sea): Geomorphic, stratigraphic and tectonic inferences

We use multibeam sonar scanning of the seafloor and high-resolution sub-bottom sonar profiling to investigate pre-Holocene geomorphic features in the Gulf of Trieste that are visible in seafloor topography. We focus on two channel-like features, the Paleorižana and Paleoreka. Sub-bottom profiles and published core log data reveal that these features represent the transgressive surface at the boundary between Pleistocene continental and Holocene marine sedimentation. The geometry of the paleosurface, the architecture, and the acoustic facies of underlying sediment bodies clearly show that this surface represents an alluvial plain containing a moderate- to low-energy floodplain. The Paleorižana feature represents a meander belt with multiple meander scars and oxbow lakes, while the Paleoreka is a single, slightly sinuous channel river with well-developed levees. Geomorphic characteristics of the two rivers are replicated in the seafloor topography in astonishing detail, despite being draped by up to 10m of Holocene marine sediments. We extract Paleoreka thalweg depths from sub-bottom profiles to construct a longitudinal channel profile, which runs approximately perpendicular to the main tectonic structures of the Gulf. We find no evidence of long-term mm-scale localized relative vertical tectonic movements which were previously inferred from repeated geodetic levelling surveys along the SW-NE oriented Slovenian coastline. We speculate that the geodetic data may instead indicate short-term interseismic deformation along the Slovenian coast, which would necessitate further investigation of tectonic activity and seismic hazard in the Gulf area.

New insights on the subsidence of Lipari island (Aeolian islands, southern Italy) from the submerged Roman age pier at Marina Lunga

Lipari island belongs to the Aeolian archipelago, located in the Southern Tyrrhenian Sea (Italy), which is one of the most active volcanic areas of the Mediterranean basin. Although this region has been settled since prehistory, only during Roman times were coastal installations built in these islands. In this study, we present and discuss data on the relative sea level change estimated from a submerged pier of Roman age dated 2100 ± 100 BP. This structure, about 140 × 60 m, is located along the coast of Marina Lunga, corresponding to the present location of the main harbor of Lipari island. This pier, which was accidentally discovered in 2008 during preliminary excavations for the construction of a new pier, is a valuable indicator of relative sea level changes and vertical land movements. Its top surface is presently located at −9.1 ± 0.05 m, while the foundations at the outer end of the pier are at −11.6 ± 0.05 m, above a shoreline placed at −13.0 ± 0.05 m. We studied this site through direct archaeological investigations and ultra-high resolution multibeam bathymetry.The current submergence of this pier can be explained by the cumulative effect of the relative sea level changes caused by the regional glacio-hydro-isostatic signal, active since the end of the last glacial maximum, and the local volcano-tectonic land subsidence. From our investigations, a relative sea level change at 12.3 ± 0.7 m with a subsidence rate at 5.79 ± 0.01 mm y−1 and an average value of volcano-tectonic contribution at 5.17 ± 0.01 m y−1 for the last 2100 ± 100 years BP, is estimated from comparison against the latest predicted sea level model for the Southern Tyrrhenian Sea. These rates of relative sea level change led to the disuse of the harbor after around the fourth century AD, in agreement with archaeological interpretations. Our results provide new insights on the recent evolution of this active volcanic area.

The creation of a model of relative vertical crustal movementS In THE POLISH territory on the basis of the data from Active Geodetic Network EUPOS (ASG EUPOS)

The creation of a model of relative vertical crustal movementS In THE POLISH territory on the basis of the data from Active Geodetic Network EUPOS (ASG EUPOS)

Modern submarine canyon feeder-system and deep-sea fan growth in a tectonically active margin (northern Sicily)

Widely used sequence stratigraphic models predict that specific facies assemblages alternate in the stratigraphy of deep-sea fans, depending on the cyclic nature of sea-level variations. Our work tests this assumption through facies reconstruction of submarine fans that are growing in a small basin along the tectonically active Sicilian margin. Connected canyons have heads close to the coastline; they can be river connected or littoral cell–connected, the first receiving sediment from hyperpycnal flows, the latter intercepting shelf sediment dispersal pathways. Hyperpycnal flows directly discharge river-born sediment into the head of the river-connected canyon and originate a large turbidite fan. A drift formed by the longshore redistribution of sediment of a nearby delta introduces sediment to the head of the littoral cell–connected canyon, forming turbidity currents that flow within the canyon to reach the basin plain. However, since sediment failure and landslide processes are common in the slope part of the system, a mixed fan, consisting of both turbidites and mass-transport deposits, is formed. Disconnected canyons, with heads at the shelf edge far from the coastline, are fed by canyon head and levee-wedge failures, resulting in mass-transport or mixed fan deposition, the latter developing when the seafloor gradient or the lithology of the failed sediment allows turbidity current formation. Connected canyons form in areas with high uplift rates, where the shelf is narrow and steep and the shelf edge is at a relatively shallow depth. Disconnected canyons develop where there are lower uplift rates or subsidence, where the shelf is large and relatively gentle with a deeper shelf edge. It is deduced that the relative vertical movements of fault-bound blocks control whether canyons are connected to the coast at the present day. The role of tectonics in controlling the canyon feeding processes and the facies of submarine fan growth during highstand periods is therefore highlighted. A further view that arises from our paper is that in active margins, the slope portion of fan systems, through seafloor instability and variations in channel gradient, is a key factor in determining the final deep-sea fan facies, regardless of the distance between the coast and the canyon. The concomitant growth of turbidites, mass-transport deposits, and mixed fans demonstrates that models that predict changes in submarine fan facies on the basis of sea-level cycles do not necessarily apply to systems developed along tectonically active margins.

Evidence of active subsidence at Basiluzzo island (Aeolian islands, southern Italy) inferred from a Roman age wharf

The Aeolian Arc (Southern Tyrrhenian Sea, Italy) is one of the most active volcanic areas of the Mediterranean basin, affected by volcanic/hydrothermal and seismic activity. Ancient populations settled this region since historical times, building coastal installations which currently are valuable archaeological indicators of relative sea level changes and vertical land movements. In this study we show and discuss data on the relative sea level change estimated from a submerged wharf of Roman age dated between 50 B.C. and 50 A.D., located at Basiluzzo Island. This structure has been studied through marine surveys and archaeological interpretations and is presently located at a corrected depth of −4.10 ± 0.2 m. We explain this submergence by a cumulative effect of the relative sea level change caused by the regional glacio-hydro-isostatic signal, active since the end of the last glacial maximum, and the local volcano-tectonic land subsidence. Finally, a total subsidence rate of 2.05 ± 0.1 mm/yr−1, with a volcano-tectonic contribution of 1.43 ± 0.1 mm/yr−1 for the last 2 ka BP, is inferred from the comparison against the latest predicted sea level curve for the Southern Tyrrhenian Sea, suggesting new evaluations of the volcano-tectonic hazard for this area of the Aeolian islands.

Constraints for the recent tectonics of the El Salvador Fault Zone, Central America Volcanic Arc, from morphotectonic analysis

Abstract We have used hypsometric analysis to improve our understanding of the current tectonic deformation and structure of El Salvador Fault Zone; a N90°E oriented strike-slip fault zone that extends 150 km through El Salvador, Central America. Our results indicate an important amount of transtensive strain along this fault zone, providing new data to understand the tectonic evolution of the Salvadorian volcanic arc. We have defined kilometric scale tectonic blocks and its relative vertical movements, length of segments with homogeneous vertical motions and lateral relay of active structures. We have identified and quantified slip-rate variations along-strike of the El Triunfo fault within El Salvador Fault Zone, ranging from 4.6 mm/year in its central parts to 1 mm/year towards the tips of the fault. This study supports the hypothesis of a recent rotation in the maximum shortening direction, and the accommodation of the current deformation through the reactivation of pre-existing structures inherited from a previous tectonic regime.

A systematic overview of the coincidences of river sinuosity changes and tectonically active structures in the Pannonian Basin

As tectonic movements change the valley slope (low-gradient reaches of valleys, in sedimentary basins), the alluvial rivers, as sensitive indicators, respond to these changes, by varying their courses to accommodate this forcing. In our study sinuosity values, a commonly used characteristic parameter to detect river pattern changes, were studied for the major rivers in the Pannonian Basin in order to reveal neotectonic influence on their planform shape.Our study area comprises the entire Pannonian Basin (330,000km2) located in eastern Central-Europe, bounded by the Alps, Carpathians and Dinarides. The studied rivers were mostly in their natural meandering state before the main river regulations of the 19th century. The last quasi-natural, non-regulated river planforms were surveyed somewhat earlier, during the Second Military Survey of the Habsburg Empire. Using the digitized river sections of that survey, the sinuosities of the rivers were calculated with different sample section sizes ranging from 5km to 80km. Depending on the bank-full discharge, also a ‘most representative’ section size is given, which can be connected to the neotectonic activity.In total, the meandering reaches of 28 rivers were studied; their combined length is 7406km. The places where the river sinuosity changed were compared to the structural lines of the “Atlas of the present-day geodynamics of the Pannonian Basin” (Horváth et al., 2006). 36 junctions along 26 structural lines were identified where the fault lines of this neotectonic map crossed the rivers. Across these points the mean sinuosity changed. Depending on the direction of the relative vertical movements, the sinuosity values increased or decreased. There were some points, where the sinuosity changed in an opposite way. Along these sections, the rivers belong to the range of unorganized meandering or there are lithological margins.Assuming that the rivers indicate on-going faulting accurately, some places were found, where positioning of the faults of the neotectonic map could be improved according to the sinuosity jumps. However, some significant sinuosity changes cannot be correlated to known faults. In these cases other factors may play a role (e.g., hydrological changes, increase of sediment discharge also can modify sinuosity). In order to clarify the origin of these changes seismic sections and other geodynamical information should be analyzed to prove or disprove tectonic relationship if hydrological reasons can be excluded.

Evidence of vertical tectonic uplift at Briatico (Calabria, Italy) inferred from Roman age maritime archaeological indicators

Calabria is one of the most complex geological regions of the Mediterranean basin, which experienced large earthquakes and uplift and is still undergoing active tectonics. Along its coasts are located archaeological sites that can be used as powerful indicators of the relative vertical movements between land and sea since their construction. This paper presents and discusses data on the relative sea-level change as estimated from maritime archaeological indicators of the last ∼2.0 ka BP existing along the Tyrrhenian coast of Briatico. These sites still show the remnants of a Roman age fish tank and a submerged breakwater about 320 m long.The palaeo sea level has been obtained measuring the functional elevation of the significant archaeological markers. Their elevation was compared against the latest predicted sea level curve for the Holocene along the Tyrrhenian coast of Calabria. As this coastal area is affected by significant and continuous vertical tectonic uplift during Pleistocene, the data show the counterbalance between coastal uplift and relative sea level change caused by the glacio-hydro-isostasy, acting since the construction of these archaeological sites. The sum of these movements determined an about null relative sea level change for this location. These data are in contrast with other part of the tectonically stable areas of the Mediterranean and provide evidence that crustal uplift continued in the last 1806 ± 50 y at a rate of 0.65 mm/y.

Holocene relative sea-level changes and vertical movements along the Italian and Istrian coastlines

Published and new data exist for relative sea-level change for 105 locations (127 samples) during the late Holocene, along the Italian (and Istrian) coasts. These data, compared with predictions (derived from two different models associated with the last glacial cycle) allowed the calculation of the tectonic vertical movements. They are based on precise measures of geomorphological and archaeological markers between 0.4 and 12.6 ka cal. BP, sampled at elevations between +7 and −51 m. In order to decipher the broad pattern of Holocene tectonic vertical movements along the Italian coastline, these data were compared with predicted sea-level curves using the most recent models published for the Mediterranean sea. Tectonic rates varied from −4.85 mm/a, in a core at Sybaris, to 5 mm/a, in the volcanic areas of Pozzuoli and Pantelleria. New MIS 5.5 (125 ka) data, mostly from the Venetian plain, are reported. In particular the depth of the base of MIS 5.5 paralic deposits found in four cores near Venezia provides a mean subsidence of 0.62 mm/a. New, precise mass spectrometer U-Th analyses on Cladocora layers from the bottom of a long core (named ENEA), indicate older ages (195.7 ± 1.6 and 161.2 ± 1.2 ka, respectively), relative to the published MIS 5.5 ages, which were based on alpha-counting U-Th data. Instrumental data obtained from tide gauges and repeated levelling measurements from the NE Adriatic and Sicily are also considered. These methods have one great advantage with respect to continuous GPS measurements and the satellite altimetric observations, in that a much greater time span is available. Although the altimetric measurements are available for 16 years, and the GPS for less than a decade, repeated levelling lines cover up to 50 years and tide gauge observations in some cases to 100 years or more. The greater time span allows for more stable differential rate estimates. The repeated levelling shows that the plain east of Mestre is subsiding (to −4 mm/a). The Messina tidal gauge demonstrates a total coseismic and post-seismic subsidence of 77 cm associated with the event of 1908, the post-seismic phase lasting for at least 13 years. The Reggio Calabria tidal station points to an uplift of this station relative to Palermo in the order of 1–2 mm/a.

Application of Rolling Dynamic Deflectometer to Forensic Studies and Pavement Rehabilitation Projects

Characterization of the load transfer of jointed plain concrete pavements requires proper tools. The rolling dynamic deflectometer (RDD) has been used successfully on many Texas Department of Transportation projects for this purpose. Applications of the RDD in forensic studies and pavement rehabilitation projects are presented. RDD deflection profiles were used to assist in diagnosing the causes of reflective cracks on SH87a, where a reflective crack relief interlayer was placed in a rehabilitation project to minimize reflective cracking. However, frequent and severe reflective cracks still occurred on SH87a in the turning and inside lanes, where traffic is lighter than in the outside lane. It was concluded that poor load transfer at joints (indicated by high relative vertical movements) was one of the main contributing factors to the reflective cracking in these two lanes. Two rehabilitation projects are also presented to show how continuous RDD deflection profiles were critical to the success of the projects. In the BU287 project, RDD profiles were used to identify successfully locations for full-depth repair in Subsection 1 and recommend a different rehabilitation strategy (remove and reconstruct) in Subsection 2 because of the significant number of joints that have a severe potential for reflective cracking. In the SH87b rehabilitation project, the RDD was employed to identify locations that need dowel bar retrofit and other locations that need full-depth repair. It is concluded that RDD data not only are able to provide 100% coverage but also offer quantifiable and objective information for forensic and rehabilitation studies in terms of relative movements at joints and cracks.

Recent vertical movements from precise levelling in the vicinity of the city of Basel, Switzerland

The southern end of the Upper Rhine Graben is one of the zones in Switzerland where recent crustal movements can be expected because of ongoing seismotectonic processes as witnessed by seismicity clusters occurring in this region. Therefore, in 1973 a control network with levelling profiles across the eastern Rhine Graben fault was installed and measured in the vicinity of the city of Basel in order to measure relative vertical movements and investigate their relationship with seismic events. As a contribution to EUCOR-URGENT, the profiles were observed a third time in the years 2002 and 2003 and connected to the Swiss national levelling network. The results of these local measurements are discussed in terms of accuracy and significance. Furthermore, they are combined and interpreted together with the extensive data set of recent vertical movements in Switzerland (Jura Mountains, Central Plateau and the Alps). In order to be able to prove height changes with precise levelling, their values should amount to at least 3–4 mm (1σ). The present investigations, however, have not shown any significant vertical movements over the past 30 years.

Raised marine sequences of Lanzarote and Fuerteventura revisited—a reappraisal of relative sea-level changes and vertical movements in the eastern Canary Islands during the Quaternary

Systematic mapping and morphosedimentary analysis of Fuerteventura and Lanzarote Islands supported by laboratory techniques (U-series mostly by TIMS, 14C analysis and allo-isoleucine measurements on biogenic carbonates from raised marine deposits, paleomagnetic and a few K/Ar measurements on volcanic formations related to marine deposits) provide a basis for constraining the age of Late Cainozoic marine units. The most complete sequences of raised marine terraces are found at similar elevations in both islands. They include up to 12 marine terraces (Episodes) at elevations between 0 m and 70 m above mean sea level (asl). At least six terraces should be of Quaternary age, and more recent than 1.2 Myr. Throughout the whole marine sequence with the exception of the Holocene terrace, the warm fauna assemblage is characterized by the presence of Ostrea virleti, Nerita emiliana, and Strombus ( S. cf. coronatus–S. cf. bubonius). However, there is a major change, highlighted by the disappearance of the first two species, below the 8–10 m terrace, that could possibly correspond to MIS 11. K–Ar measurements allow an estimate for mean uplift rate of 1.7 cm/ka during the last million years. The present elevation of the Last Interglacial deposits (about 1 and 2 m asl) shows discontinuous vertical movements with possibly a reverse trend since MIS 9 in eastern Canary Islands.

Regional Cenozoic uplift and subsidence events in the southeastern North Sea

The Paleocene topography of the Fennoscandian Shield is indicated by outbuilding towards the Central Trough and the Ringkøbing-Fyn High. From Eocene until Pliocene time three events of relative vertical movements are indicated by changes in outbuilding directions and reflection termination patterns in the central North Sea. The first event of uplift was in the Eocene and resulted in relative uplift of the Mid North Sea High and contemporary subsidence east of it, indicated by a change in outbuilding from north to west. A second event of uplift is indicated to the north of the study area at the Eocene-Oligocene boundary by renewed southward outbuilding in the Norwegian-Danish Basin. In Miocene until Early Pliocene time a relatively stationary, almost east-west striking, basin margin was probably located to the north along the Tornquist Zone as indicated by the continued outbuilding towards the Ringk0bing Fyn High. A third event of relative uplift is indicated east of the study area by changes in the Pliocene outbuilding pattern. After the first event of uplift it appears that the deepest parts of the Eocene North Sea Basin were located more easterly than the deepest parts are today. Apparently the two latest uplift events north and east of the study area were related to movements of, or along the Tornquist Zone or to regional uplift of the Fennoscandian Shield finally resulting in the presentday configuration of the North Sea.

Resilient floor system

A resilient floor (A) is disclosed assembled on a base surface (10) to provide a resilient floor (36) which comprises a plurality of sub-floor sections (B) arranged generally side-by-side. A resilient layer of material (62) is carried generally co-extending underneath the sub-floor sections. A slot (38,74) and widened groove (40) accommodate a fastening member (51,71) which includes lateral flanges (58,60) and (78,80) which limit upward movement of sub-floor sections (B). Flooring strips (D) are nailed to the sub-floor sections so that the flooring strips move integrally together in relative vertical movements relative to the fastening strips (51,71). Resilient layer (62) urges sub-floor sections (B) and integral flooring strips (D) upwardly such that downward forces produced by activity on the floor (36) are provided with a degree of resiliency.

Vertical movement in orogenic belts and the timing of metamorphism relative to deformation

Summary Any phase of deformation in an orogenic belt that causes relative vertical movements of bodies of rock by a few kilometres or more should have a recognizable imprint in the metamorphic history. The effect seen in a P-T-t path will depend on whether the rock body examined moved relatively up or down in the orogenic pile. An upthrown block is predicted to cool soon after the onset of movement, but the resulting P-T path will be insignificantly different to that resulting from a cycle of thickening and erosion. A downthrown block will undergo renewed heating after movement, and evidence of the earlier metamorphic history will probably be overprinted. It is suggested that the recognition of phases of relative vertical movement in an orogenic belt is best made by combined studies of deformation-metamorphism textural relationships, and P-T-t paths. The Lukmanier Pass area of the Alps illustrates the textural patterns predicted: here, a phase of deformation immediately post-dates the metamorphic peak, suggesting uplift of the area relative to the Helvetic nappes to the north.

Monthly mean sea levels in Greece during 1969–1983 compared to relative vertical land movements measured over different timescales

Sea level data from 16 tide gauge stations in Greece have been used in an analysis of the seasonal cycle of mean sea level in Greek waters together with an investigation of the interannual variability of sea level in the region for the period 1969–1983. The recorded seasonal cycle is found to vary considerably across the area and to agree well with sea level observations from neighbouring coastlines. The Greek data result in knowledge of the mean sea level seasonal cycle being now available from throughout the northeastern Mediterranean. An overall drop of sea levels is observed during the mid-1970's, while the larger peaks and dips in the records are found to be coherent over the whole area and, on several occasions, to be general to the entire northern Mediterranean. The tide gauge data set has also provided measurements of the secular trends in relative mean sea levels over the same 15-year period. A wide geographical variation of sea level trends is observed spanning a range from +21 to −11 mm/yr (measured relative to sea levels at Katakolon). After inversion, these measurements provide estimates of relative vertical land movements of the present epoch which can be compared to those obtained from archaeological and geological sources, i.e. changes over timescales of thousands, tens of thousands and tens of millions of years. Differences in the sign and magnitude of the relative vertical land movements of this geologically complicated region obtained from the different data sets are discussed in detail. It is shown that the direction of vertical movement recorded by the tide gauges correlates well with that observed over longer periods and that, with relatively few exceptions, sites which are uplifting (submerging) relatively rapidly over one timescale are uplifting (submerging) relatively rapidly at all timescales. While the rate of vertical movement throughout the Aegean and southern Greece usually preserves the same sign at a given site over timescales of 10 1–10 7 yrs, its magnitude decreases approximately by a factor ( 1 T ) 0.4 , where T is the measurement averaging period.

組積剛体系の衝突転倒振動の数値計算法 : その 1 垂直平面内の運動

A numerical method is discussed for analyzing non-linear dynamic response of columns consisting of stacked block elements. In this report (Part I), a series of columns placed in a vertical plane with boundary structures is considered for the analytical model. Each column is formed by a series of stacked elements constrained by some mechanisms which restrict the relative horizontal and vertical movements but allow the rocking motion between elements. Theoretical equations are derived from the principle of conservation of translational and rotaional momenta for each block motion, furthermore collision theory based on a coefficient of restitution is applied for the horizontal collision between adjacent blocks. By using these a equations, computer code "COLLAN2V" has been developed by selecting appropriate numerical methods through parametric study. To show the feasibility of the code, presented are several simple examples such as frequency response of a 10-stacked column surrounded by walls.